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日本</span></span></div></a><a href='https://aqicn.org/faq/es/' class='lang-es'><div class='item'><div class='flag sprite-isprt-web-es'></div><span class='name'>Spanish <span>- español</span></span></div></a><a href='https://aqicn.org/faq/kr/' class='lang-ko'><div class='item'><div class='flag sprite-isprt-web-kr'></div><span class='name'>Korean <span>- 한국의</span></span></div></a><a href='https://aqicn.org/faq/ru/' class='lang-ru'><div class='item'><div class='flag sprite-isprt-web-ru'></div><span class='name'>Russian <span>- русский</span></span></div></a><a href='https://aqicn.org/faq/hk/' class='lang-zh-TW'><div class='item'><div class='flag sprite-isprt-web-hk'></div><span class='name'>Traditional Chinese <span>- 繁體中文</span></span></div></a><a href='https://aqicn.org/faq/fr/' class='lang-fr'><div class='item'><div class='flag sprite-isprt-web-fr'></div><span class='name'>French <span>- Francais</span></span></div></a><a href='https://aqicn.org/faq/pl/' class='lang-pl'><div class='item'><div class='flag sprite-isprt-web-pl'></div><span class='name'>Polish <span>- Polski</span></span></div></a><a href='https://aqicn.org/faq/de/' class='lang-de'><div class='item'><div class='flag sprite-isprt-web-de'></div><span class='name'>German <span>- Deutsch</span></span></div></a><a href='https://aqicn.org/faq/pt/' class='lang-pt'><div class='item'><div class='flag sprite-isprt-web-br'></div><span class='name'>Portuguese <span>- Português</span></span></div></a><a href='https://aqicn.org/faq/vn/' class='lang-vi'><div class='item'><div class='flag sprite-isprt-web-vn'></div><span class='name'>Vietnamese <span>- Tiếng Việt</span></span></div></a><a href='https://aqicn.org/faq/it/' class='lang-it'><div class='item'><div class='flag sprite-isprt-web-it'>🇮🇹</div><span class='name'>Italian <span>- Italiano</span></span></div></a><a href='https://aqicn.org/faq/id/' class='lang-id'><div class='item'><div class='flag sprite-isprt-web-id'>🇮🇩</div><span class='name'>Indonesian <span>- bahasa Indonesia</span></span></div></a><a href='https://aqicn.org/faq/nl/' class='lang-nl'><div class='item'><div class='flag sprite-isprt-web-nl'>🇳🇱</div><span class='name'>Dutch <span>- Nederlands</span></span></div></a><a href='https://aqicn.org/faq/fa/' class='lang-fa'><div class='item'><div class='flag sprite-isprt-web-ir'>🇮🇷</div><span class='name'>Persian <span>- فارسی</span></span></div></a><a href='https://aqicn.org/faq/th/' class='lang-th'><div class='item'><div class='flag sprite-isprt-web-th'>🇹🇭</div><span class='name'>Thai <span>- ภาษาไทย</span></span></div></a><a href='https://aqicn.org/faq/hu/' class='lang-hu'><div class='item'><div class='flag sprite-isprt-web-hu'>🇭🇺</div><span class='name'>Hungarian <span>- Magyar</span></span></div></a><a href='https://aqicn.org/faq/el/' class='lang-el'><div class='item'><div class='flag sprite-isprt-web-gr'>🇬🇷</div><span class='name'>Greek <span>- Ελληνικά</span></span></div></a><a href='https://aqicn.org/faq/ro/' class='lang-ro'><div class='item'><div class='flag sprite-isprt-web-ro'>🇷🇴</div><span class='name'>Romanian <span>- Română</span></span></div></a><a href='https://aqicn.org/faq/bg/' class='lang-bg'><div class='item'><div class='flag sprite-isprt-web-bg'>🇧🇬</div><span class='name'>Bulgarian <span>- български</span></span></div></a><a href='https://aqicn.org/faq/ur/' class='lang-ur'><div class='item'><div class='flag sprite-isprt-web-pk'>🇵🇰</div><span class='name'>Urdu <span>- اردو</span></span></div></a><a href='https://aqicn.org/faq/hi/' class='lang-hi'><div class='item'><div class='flag sprite-isprt-web-in'>🇮🇳</div><span class='name'>Hindi <span>- हिंदी</span></span></div></a><a href='https://aqicn.org/faq/ar/' class='lang-ar'><div class='item'><div class='flag sprite-isprt-web-ae'>🇦🇪</div><span class='name'>Arabic <span>- العربية</span></span></div></a><a href='https://aqicn.org/faq/sr/' class='lang-sr'><div class='item'><div class='flag sprite-isprt-web-rs'>🇷🇸</div><span class='name'>Serbian <span>- Српски</span></span></div></a><a href='https://aqicn.org/faq/bn/' class='lang-bn'><div class='item'><div class='flag sprite-isprt-web-bd'>🇧🇩</div><span class='name'>Bangla <span>- বাংলা</span></span></div></a><a href='https://aqicn.org/faq/bs/' class='lang-bs'><div class='item'><div class='flag sprite-isprt-web-ba'>🇧🇦</div><span class='name'>Bosnian <span>- босански</span></span></div></a><a href='https://aqicn.org/faq/hr/' class='lang-hr'><div class='item'><div class='flag sprite-isprt-web-hr'>🇭🇷</div><span class='name'>Croatian <span>- hrvatski</span></span></div></a><a href='https://aqicn.org/faq/tr/' class='lang-tr'><div class='item'><div class='flag sprite-isprt-web-tr'>🇹🇷</div><span class='name'>Turkish <span>- Türkçe</span></span></div></a><a href='https://aqicn.org/faq/uk/' class='lang-uk'><div class='item'><div class='flag sprite-isprt-web-ua'>🇺🇦</div><span class='name'>Ukrainian <span>- українська</span></span></div></a><a 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break-all;'>Share: <a href='http://aqicn.org/faq/'>aqicn.org/faq/</a></i><br><script>function ntfConf() { return {page:"faq", divId:"ntf-body-first"} }</script><div id='ntf-body-first' style='display:none;font-size:20px;'></div><br><div class='faqtoc'><div style='line-height:1.5;'><center><img src='/air/experiments/images/aqi-transparent.png' width=200 style='max-width:100%;' class='faqtoclogo'></center><div class='faqtoctitle'>Frequently asked questions content:</div><br><div class='faq-toc-item'><a href='https://aqicn.org/scale/'>AQI Scale: What do the colors and numbers mean?</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/using-statistical-distances-for-real-time-sensor-networks-validation/'>Using Statistical Distances for Real-time Sensor Networks Validation</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2017-01-10/nitrogen-dioxyde-no2-in-our-atmosphere/'>Nitrogen Dioxyde (NO<sub>2</sub>) in our atmosphere</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2016-08-10/ozone-aqi-scale-update/'>Ozone AQI Scale update</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2016-02-28/air-quality-forecasting-in-northern-india/'>Air Quality Forecasting in Northern India</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-11-05/a-visual-study-of-wind-impact-on-pm25-concentration/'>A visual study of Wind impact on PM<sub>2.5</sub> Concentration</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-10-28/unep-air-quality-monitoring-station/'>UNEP Air Quality Monitoring Station</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-09-20/asean-air-quality-tile-map-service/'>Asean Air Quality Tile Map Service</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-09-18/map-web-service-real-time-air-quality-tile-api/'>Map Web Service: Real-time Air Quality Tile API</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-09-06/ozone-aqi-using-concentrations-in-milligrams-or-ppb/'>Ozone AQI: Using concentrations in <i>milligrams</i> or <i>ppb</i>?</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-09-03/air-quality-scale-in-poland/'>Air Quality Scale in Poland</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-07-28/air-quality-widget-new-improved-feed/'>Air Quality Widget - New Improved Feed</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-07-18/real-time-air-quality-monitoring-in-indonesia/'>Real-time Air Quality monitoring in Indonesia</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-07-16/air-quality-scale-in-quebec-and-montreal/'>Air Quality Scale in Quebec and Montreal</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-07-01/translation-for-polish-is-now-available/'>Translation for Polish is now available</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-06-08/wind-and-air-pollution-forecast-in-quito/'>Wind and Air Pollution Forecast in Quito</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-06-03/overview-of-hong-kongs-air-quality-health-index/'>Overview of Hong Kong's Air Quality Health Index</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-05-30/air-quality-forecast-in-south-america/'>Air Quality Forecast in South America</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-05-18/ground-ozone-air-quality-index-update-with-instant-cast/'>Ground Ozone Air Quality Index update with Instant Cast</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-05-16/world-health-organization-2014-air-pollution-ranking/'>World Health Organization: 2014 Air Pollution Ranking</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-05-15/india-national-air-quality-index/'>Overview of India's National Air Quality Index</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-05-10/a-comparison-of-latin-american-air-quality-scales/'>A comparison of Latin American Air Quality Scales</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-05-02/south-asian-air-quality-scales-malaysia-and-thailand/'>South Asian Air Quality Scales: Malaysia and Thailand</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-04-28/real-time-air-quality-in-the-balkan-peninsula/'>Real-time Air Quality in the Balkan Peninsula</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-04-26/nasa-earth-observations-and-tools-for-air-quality-applications/'>NASA - Earth Observations and Tools for Air Quality Applications</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-04-08/air-quality-in-africa-and-middle-east/'>Air Quality in Africa and Middle East</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-03-23/air-quality-forecasting-how-accurate-can-it-be/'>Air Quality Forecasting - How accurate can it be?</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-03-20/a-comparison-of-worldwide-air-quality-scales-part-1/'>A comparison of worldwide Air Quality Scales - Part 1</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/'>A Beginner's Guide to Air Quality Instant-Cast and Now-Cast. </a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-02-23/south-asia-real-time-air-quality-monitoring-project/'>South Asia Real-time Air Quality Monitoring Project</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-02-15/satellite-air-quality-monitoring-introduction-to-the-nasa-worldview/'>Satellite Air Quality monitoring: Introduction to the NASA WorldView</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2015-02-08/visual-recognising-the-air-quality-index-a-case-applied-to-hanoi/'>Visual recognising the Air Quality Index - a case applied to Hanoi</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2014-10-28/android-app-update-now-with-embedded-map-and-wind-forecast/'>Android app. update: now with embedded map and wind forecast.</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2014-10-06/clean-air-initiative-and-the-better-air-quality-conference-2014/'>Clean Air Initiative and the Better Air Quality Conference 2014</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2014-09-06/australian-air-quality-comparison-with-the-us-epa-aqi-scale/'>Australian Air Quality: Comparison with the US EPA AQI scale.</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2014-08-01/haier-air-box-can-it-provide-any-useful-air-quality-information/'>Haier air box: Can it provide any useful Air Quality information?</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2014-07-27/android-app-update-now-with-notifications-and-automatic-location-finder/'>Android app. update: now with notifications and automatic location finder.</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2014-07-21/windows-mobile-application-now-available-from-the-microsoft-app-store/'>Windows Mobile Application now available from the Microsoft App-Store</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-12-28/updated-android-application-30-now-available-for-download/'>Updated Android application 3.0 now available for download.</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-10-21/dylos-air-particule-conter-experiment-maintenance/'>Dylos Air Particule Conter experiment maintenance.</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-09-09/revised-pm25-aqi-breakpoints/'>Revised PM<sub>2.5</sub> AQI breakpoints</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1/'>Dylos Air Particule counter experimentation, part 1.</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-06-25/singapore-psi-and-pm25-aqi-why-is-there-a-difference-between-the-two-readings/'>Singapore PSI and PM<sub>2.5</sub> AQI: Why is there a difference between the two readings?</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-05-20/shenyang-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shenyang/'>Shenyang PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 3 measurement stations in Shenyang</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-02-07/air-quality-designation-update-to-the-epa-airnow-standard/'>Air Quality Designation: Update to the EPA AirNow standard</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-02-03/can-masks-really-filter-the-particulate-matter-as-small-as-pm25/'>Can masks really filter the particulate matter as small as PM<sub>2.5</sub>?</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-02-02/why-is-pm25-often-higher-than-pm10/'>Why is PM2.5 often higher than PM10? Is PM10 still a relevant measure?</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-01-19/shanghai-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shanghai/'>Shanghai PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 3 measurement stations in Shanghai</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-01-11/chengdu-pm25-main-aqi-update-comparative-pm25-data-for-2-measurement-stations-in-chengdu/'>Chengdu PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 2 measurement stations in Chengdu</a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/faq/2013-01-11/beijing-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-beijing/'>Beijing PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 3 measurement stations in Beijing</a></div><center><div class='faq-toc-item-separator'></div></center><br><img src='/air/experiments/images/pollution.png' style='max-width:50%' width=286 class='faqtoclogo'><br><div class='faqtoctitle'>Air quality experiments:</div><div class='faq-toc-item'><a href='https://aqicn.org/experiments/south-korea-pm25-air-quality/'><i18n>Simulating PM2.5 Air Quality when only PM10 is available: case study for South Korea</i18n></a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/experiments/haier-air-box/'><i18n>The Haier AirBox device. Does it provide any useful information?</i18n></a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/experiments/what-is-the-dylos-monitor-actually-measuring/'><i18n>Dylos monitor: What is it actually measuring? PM2.5, PM10 or PM0.5?</i18n></a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/sensor/shinyei/'><i18n>The Shinyei experiment: Real-time Air Quality readings from Beijing</i18n></a></div><center><div class='faq-toc-item-separator'></div></center><div class='faq-toc-item'><a href='https://aqicn.org/sensor/beijing/sanlitun/'><i18n>The Dylos experiment: Real-time Air Quality readings from Beijing</i18n></a></div><center><div class='faq-toc-item-separator'></div></center><br>For a more general presentation of the quality research and experimentations, check <a href='https://aqicn.org/experiments/'>our research and development page</a>.</a><br><br><br></div></div><article><div><a href='https://aqicn.org/scale/' class='faqlisttitle'>AQI Scale: What do the colors and numbers mean?</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>January 17<sup>th</sup> 2024</small><div><small>https://aqicn.org/scale/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/scale/"'><p>Are you wondering what the different colors and numbers below mean?</p><center style='margin-bottom:15px;'><div style='display:inline-block;width:50px;text-align:center;padding:3px;margin:3px;'><div class='saqi item' style='text-shadow: 1px 1px 0 #000000;color:#ffffff;background-color:#009966;'>50</div></div><div style='display:inline-block;width:50px;text-align:center;padding:3px;margin:3px;'><div class='saqi item' style='text-shadow: 1px 1px 0 #ffffff;color:#000000;background-color:#ffde33;'>100</div></div><div style='display:inline-block;width:50px;text-align:center;padding:3px;margin:3px;'><div class='saqi item' style='text-shadow: 1px 1px 0 #ffffff;color:#000000;background-color:#ff9933;'>150</div></div><div style='display:inline-block;width:50px;text-align:center;padding:3px;margin:3px;'><div class='saqi item' style='text-shadow: 1px 1px 0 #000000;color:#ffffff;background-color:#cc0033;'>200</div></div><div style='display:inline-block;width:50px;text-align:center;padding:3px;margin:3px;'><div class='saqi item' style='text-shadow: 1px 1px 0 #000000;color:#ffffff;background-color:#660099;'>300</div></div><div style='display:inline-block;width:50px;text-align:center;padding:3px;margin:3px;'><div class='saqi item' style='text-shadow: 1px 1px 0 #000000;color:#ffffff;background-color:#7e0023;'>500</div></div></center><p>The numbers are the Air Quality <a>Indexes</a>, which is based on a scale from 0 (good) to 500 (bad).The colors correspond to the different health impact categories (good, moderate, unhealthy... hazardous)</p><br><center style='margin-bottom:15px;'><div style='font-size:66%;border-bottom:5px solid #009966;background-color:#ccebe0;display:inline-block;text-align:center;padding:3px;margin:3px;'>Good</div><div style='font-size:66%;border-bottom:5px solid #ffde33;background-color:#fff8d6;display:inline-block;text-align:center;padding:3px;margin:3px;'>Moderate</div><div style='font-size:66%;border-bottom:5px solid #ff9933;background-color:#ffebd6;display:inline-block;text-align:center;padding:3px;margin:3px;'>Unhealthy for Sensitive Groups</div><div style='font-size:66%;border-bottom:5px solid #cc0033;background-color:#f5ccd6;display:inline-block;text-align:center;padding:3px;margin:3px;'>Unhealthy</div><div style='font-size:66%;border-bottom:5px solid #660099;background-color:#e0cceb;display:inline-block;text-align:center;padding:3px;margin:3px;'>Very Unhealthy</div><div style='font-size:66%;border-bottom:5px solid #7e0023;background-color:#e5ccd3;display:inline-block;text-align:center;padding:3px;margin:3px;'>Hazardous</div></center> <br><center><a href='https://aqicn.org/scale/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/using-statistical-distances-for-real-time-sensor-networks-validation/' class='faqlisttitle'>Using Statistical Distances for Real-time Sensor Networks Validation</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>April 28<sup>th</sup> 2020</small><div><small>https://aqicn.org/faq/using-statistical-distances-for-real-time-sensor-networks-validation/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/using-statistical-distances-for-real-time-sensor-networks-validation/"'> <div style='padding-left:10px;float:right;max-width:50%;width:300px;text-align:center;'> <img src='/air-faq/using-statistical-distances-for-real-time-sensor-networks-validation/asset/kernel-densities.jpg' width=100%> <div style='font-size: 80%'> Overlapping kernel densities,<br> (<a href='https://stats.stackexchange.com/questions/122857/how-to-determine-overlap-of-two-empirical-distribution-based-on-quantiles' target=_>credits</a>) </div> </div> <p> Back in 2008, when the World Air Quality project started, all of the existing air quality monitoring stations where based on highly professional and expensive BAM and TOEM technology. This kind of stations are always maintained by professional and highly qualified operators - and this ensures that the output of this station can be trusted. </p> <p> 12 years later, the BAM and TOEM stations still do exist. But with the development of laser scattering technology and low-cost dust sensor, the BAM and TOEM stations are now outnumbered by immense and dense low-cost sensor networks. Nowdays, there are just so many of those networks - to name a few: urad, luft-daten, airqo, airbg, opensense, yakkaw, econet, airkaz, ccdc, ambente, green air, etc.. </p> <br><center><a href='https://aqicn.org/faq/using-statistical-distances-for-real-time-sensor-networks-validation/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2017-01-10/nitrogen-dioxyde-no2-in-our-atmosphere/' class='faqlisttitle'>Nitrogen Dioxyde (NO<sub>2</sub>) in our atmosphere</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>January 10<sup>th</sup> 2017</small><div><small>https://aqicn.org/faq/2017-01-10/nitrogen-dioxyde-no2-in-our-atmosphere/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2017-01-10/nitrogen-dioxyde-no2-in-our-atmosphere/"'> <div style='padding-left:10px;float:right;max-width:50%;width:300px;text-align:center;'> <img src='/air/view/faq/images/no2-atmosphere/tropospheric-no2-column.png' width=100%> <div style='font-size: 80%'> Introduction to Weather and Climate,<br>Univ. of Arizona (<a href='http://www.temis.nl/airpollution/no2.html' target=_>credits</a>) </div> </div> <p class='bigletter'> A common question asked is why are nitrogen dioxide (NO<sub>2</sub>), sulphur dioxide (SO<sub>2</sub>) and carbon monoxide (CO) concentrations always so low and is measuring them useful? </p> <p> To highlight the importance of monitoring these substances this article is going to explain where these pollutants come from and how to they affect our health and the environment. </p> <p> To keep things short this article will just focus on NO2. </p> <br><center><a href='https://aqicn.org/faq/2017-01-10/nitrogen-dioxyde-no2-in-our-atmosphere/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2016-08-10/ozone-aqi-scale-update/' class='faqlisttitle'>Ozone AQI Scale update</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>August 10<sup>th</sup> 2016</small><div><small>https://aqicn.org/faq/2016-08-10/ozone-aqi-scale-update/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2016-08-10/ozone-aqi-scale-update/"'> <div style='padding-left:10px;float:right;max-width:50%;width:300px;text-align:center;'> <img src='/images/nowcast/ozone-as-a-secondary-pollutant.png' width=100%> <div style='font-size: 80%'> Introduction to Weather and Climate,<br>Univ. of Arizona (<a href='http://www.atmo.arizona.edu/courses/spring16/atmo170a1s1/HOME.html' target=_>credits</a>) </div> </div> <p class='bigletter'> It is already several months since the US EPA updated its AQI standard for Ozone 8 hours breakpoints. This is definitely a positive step towards strengthening Air Quality in the USA, since the US EPA Standard was actually among of the least conservative standard for Ozone, compared, for instance, to similar standards in India, China or Europe! </p> <p> But more interestingly, <a href='https://www.airnow.gov'>AirNow</a> recently took a step further by introducing the Ozone <a href='/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/'>NowCast</a> formula, which allows to use the weighted 8 hours breakpoint standard in place of the 1 hour breakpoint. This change, which the AirNow team did not widely communicate to the public, makes quite a change to the way Ozone AQI is reported, and this is what we will be looking at in this article. </p> <br><center><a href='https://aqicn.org/faq/2016-08-10/ozone-aqi-scale-update/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2016-02-28/air-quality-forecasting-in-northern-india/' class='faqlisttitle'>Air Quality Forecasting in Northern India</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>February 28<sup>th</sup> 2016</small><div><small>https://aqicn.org/faq/2016-02-28/air-quality-forecasting-in-northern-india/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2016-02-28/air-quality-forecasting-in-northern-india/"'> <div style='padding-left:10px;float:right;max-width:50%;width:300px;text-align:center;'> <img src='/images/india/chimborazo1.jpg' width=100%> <div><small> Chimborazo Mountain (<a href='http://www.ii.uib.no/~petter/mountains/5000mtn/chimborazo.html'>credits</a>) </div> </div> <p class='bigletter'> During the past months, the World Air Quality team has been working on analyzing several new Air Quality forecast models, as well as improving the Air Quality forecast model demonstrator. </p> <p> This article will present the latest forecast model demonstrator, which is based on the Gridded Population of the World (<a href='http://beta.sedac.ciesin.columbia.edu/data/collection/gpw-v4'>GPW</a>), and which will be applied to analyze the Air Quality forecast for the Northern India region (including Bangladesh, Pakistan and Nepal). </p> <br><center><a href='https://aqicn.org/faq/2016-02-28/air-quality-forecasting-in-northern-india/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-11-05/a-visual-study-of-wind-impact-on-pm25-concentration/' class='faqlisttitle'>A visual study of Wind impact on PM<sub>2.5</sub> Concentration</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>November 5<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-11-05/a-visual-study-of-wind-impact-on-pm25-concentration/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-11-05/a-visual-study-of-wind-impact-on-pm25-concentration/"'> <div style='float:right;padding-left:20px;text-align:center;width:300px; max-width:50%;'> <img src="/images/forecast/dust-storm-nasa.png" style='max-width:100%;'> <br> <small> A perfect dust storm <small>(<a href='http://www.nasa.gov/multimedia/imagegallery/image_feature_989.html'>attribution</a>)</small> </small> </div> <p> We have been writing quite a few times about the influence of wind on air pollution, and how strong winds (or, to be more precise, strong <a href='http://www.env.gov.bc.ca/epd/bcairquality/readings/ventilation-index.html'>ventilation</a>) can help to clean the air in a very short time. But we never had the opportunity to create on a dynamic visualization of this phenomenon, so this is what this article will be writing about. </p> <br><center><a href='https://aqicn.org/faq/2015-11-05/a-visual-study-of-wind-impact-on-pm25-concentration/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div style='float:right;padding-left:20px;text-align:center;line-height:1.2;max-width:50%'><img src='/images/unep-monitoring-station/unep-aqms-logo.jpg' width=180px style='max-width:100%;'><br><div style='font-size:80%;margin:10px 0;'></div></div><div><a href='https://aqicn.org/faq/2015-10-28/unep-air-quality-monitoring-station/' class='faqlisttitle'>UNEP Air Quality Monitoring Station</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>October 28<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-10-28/unep-air-quality-monitoring-station/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-10-28/unep-air-quality-monitoring-station/"'> <p> It is almost two months since our colleagues from the <a href='http://unep.org'>UNEP</a> have been making an interesting move towards promoting the idea that Air Quality is as important as any other business within the United Nations. They started to invest in this domain, and came up with the excellent initiative to create an open footprint for affordable Air Quality Monitoring Stations. </p> <br><center><a href='https://aqicn.org/faq/2015-10-28/unep-air-quality-monitoring-station/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-09-20/asean-air-quality-tile-map-service/' class='faqlisttitle'>Asean Air Quality Tile Map Service</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>September 20<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-09-20/asean-air-quality-tile-map-service/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-09-20/asean-air-quality-tile-map-service/"'> <div style='float:right;padding-left:20px;text-align:center;line-height:1.2;'> <img src="/images/map-web-services/asean.png" width=180> </div> <p class='bigletter'> This is a small contribution form the <a href='/home/'>World Air Quality Index</a> project to the ASMC - ASEAN Specialised Meteorological Centre (<a href='http://asmc.asean.org/'>asmc.asean.org</a>) during this heavy period of Haze in South Asia. </p> <br><center><a href='https://aqicn.org/faq/2015-09-20/asean-air-quality-tile-map-service/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-09-18/map-web-service-real-time-air-quality-tile-api/' class='faqlisttitle'>Map Web Service: Real-time Air Quality Tile API</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>September 18<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-09-18/map-web-service-real-time-air-quality-tile-api/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-09-18/map-web-service-real-time-air-quality-tile-api/"'> <div style='float:right;padding-left:20px;text-align:center;line-height:1.2;'> <img src="/images/map-web-services/map-overlay.png" width=200 width=200 > <br> <small> Map Overlay Process<br> <small><small>(Attribution: <a href='https://saylordotorg.github.io/text_essentials-of-geographic-information-systems/index.html'> Essentials of<br> Geographic Information Systems</a> )</small></small> </small> </div> <p> We have been recently cooperating with quite a few more EPAs (environmental protection agencies) world-wide. Among all the requests which we have had, it is actually to provide a Web Map Service so that the EPA themselves can include the real-time Air Quality data onto the map from their website. </p> <p> One of the obvious advantages of using such a map web service from us is to benefit from the trans-boundary data which we are curating, i.e. a world-wide Air Quality information is provided without country boundary limits. </p> <p> The second advantage is not only that this is a free service, but it is also completely compatible with standard map technologies from google, bing or leaflet, which allows a quick and easy integration with any existing website. </p> <br><center><a href='https://aqicn.org/faq/2015-09-18/map-web-service-real-time-air-quality-tile-api/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-09-06/ozone-aqi-using-concentrations-in-milligrams-or-ppb/' class='faqlisttitle'>Ozone AQI: Using concentrations in <i>milligrams</i> or <i>ppb</i>?</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>September 6<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-09-06/ozone-aqi-using-concentrations-in-milligrams-or-ppb/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-09-06/ozone-aqi-using-concentrations-in-milligrams-or-ppb/"'> <p class="bigletter"> The ambient <a href='https://en.wikipedia.org/wiki/Ozone'>Ozone</a>, refered as O<sub>3</sub> and also called called ground-level or <a href='https://en.wikipedia.org/wiki/Troposphere'> tropospheric</a> Ozone impacts everyone on earth regardless of the country, as shown on the image on the right . </p> <div style='margin-top:-30px;float:right;padding-left:20px;text-align:center;line-height:1.2;'> <div style='font-size:66%;margin-bottom:10px;'> Afternoon ground level Ozone concentration in July 2011 </div> <img src="/images/ozone-units/ground-level-ozone-concentration-july-2011.jpg" width=380> <br> <small> <small><small>(Attribution: <a href='http://www.wmo.int/pages/prog/arep/gaw/reactive_gases.html'> WMO GAW research on reactive gases</a> )</small></small> </small> </div> <p> Unlike particulate matter (PM<sub>2.5</sub>), the ground-level Ozone is not emitted directly. It is instead produced through a series of chemical reactions that occur in presence of nitrogen oxides, volatile organic compounds, sunlight and high temperatures, as shown on the following visual: </p> <center> <img src="/images/ozone-units/ground-ozone-how-does-it-work.png" style='max-width:100%'> </center> <p> Quantifying the impact of this ground level Ozone on Health is done via the Air Quality Index standard which each country defines. What is interesting is that half of the world is using a standard based on milligrams measurement, while the rest is using ppb based measurement. But is this really a problem? This is what we will be looking at in this article. </p> <br><center><a href='https://aqicn.org/faq/2015-09-06/ozone-aqi-using-concentrations-in-milligrams-or-ppb/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-09-03/air-quality-scale-in-poland/' class='faqlisttitle'>Air Quality Scale in Poland</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>September 3<sup>rd</sup> 2015</small><div><small>https://aqicn.org/faq/2015-09-03/air-quality-scale-in-poland/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-09-03/air-quality-scale-in-poland/"'> <style> table.fancy { border: 2px solid black; border-spacing: 0px; background: white; } table.fancy td { margin: 0px; padding: 3px; text-align: center; border-bottom: solid 1px #DEDEDE; border-right: solid 1px #DEDEDE; font-size: 13px; } table.fancy tr:hover { background: #9AC9FF; } </style> <div style='float:right;padding-left:20px;text-align:center;'> <img src="/images/aqi-scales/wios.png" width=200> <br> <small> Inspekcja Ochrony Środowiska.<br> <small>(Inspection of Environmental Protection)</small> </small> </div> <p class="bigletter"> The Air Quality data for <a href='/map/poland/'>Poland</a> has been available for a while, but we recently got few questions about the AQI scale used by the <i>Inspekcja Ochrony Środowiska</i>, i.e. the regional inspections of Environmental Protection, and how it differs with the scale used on the World Air Quality Index project. One of them is from Sylwia, who asked: </p> <blockquote> <p> I am confused with all those numbers, and why there is a difference with the numbers shown on the Warsaw EPA website. </p> <p> Could you please kindly inform me about the source of the data in Warsaw and the reliability of the data you provide with? </p> </blockquote> <p> This is actually a very good question, since, when it comes to data, no one should take data as "granted" (refering to the excellent <a href='https://www.ted.com/talks/talithia_williams_own_your_body_s_data?language=en'> TED talk</a> from <a href='https://www.math.hmc.edu/~twilliams/'>Talithia Williams</a> on 'Own your body's data'). This is also the reason why the World Air Quality Index project exists, i.e. to explain every one how to understand the number behind air pollution. </p> <br> <br><center><a href='https://aqicn.org/faq/2015-09-03/air-quality-scale-in-poland/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-07-28/air-quality-widget-new-improved-feed/' class='faqlisttitle'>Air Quality Widget - New Improved Feed</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>July 28<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-07-28/air-quality-widget-new-improved-feed/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-07-28/air-quality-widget-new-improved-feed/"'> <div style='float:right;padding-left:10px;border:0px solid black;'> <center> <span style='color:#9b9b9b;font-family: arial, sans-serif;font-size:88px;'>{<span style="font-size:60px;font-family: Georgia, Times, 'Times New Roman', serif;color:black;margin-bottom:10px;"> widget <span style='color:#9b9b9b'>:</span> feed </span>}</span> <br> <br> </div> <p class='bigletter'> In order to improve the integration of our AQI widgets within external websites, we have developped a new widget API feed. Compared to the existing widget feed, this new API feed provides much more flexibility for the integration, but also many more options for customzing the widget appearance. </p> <center> <img src='/images/widget-feed/widget-feed-banner.png' style='max-width:100%'> </center> <br> <center><a href='https://aqicn.org/faq/2015-07-28/air-quality-widget-new-improved-feed/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-07-18/real-time-air-quality-monitoring-in-indonesia/' class='faqlisttitle'>Real-time Air Quality monitoring in Indonesia</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>July 18<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-07-18/real-time-air-quality-monitoring-in-indonesia/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-07-18/real-time-air-quality-monitoring-in-indonesia/"'> <div style='float:right;padding-left:20px;text-align:center;'>  <img src="/images/indonesia-philippines/id-aq-stations-map-1.380.jpg" width=320 height=320> <br> <small> </small> </div> <p class='bigletter'> Real-time Air Quality data for is now available for Indonesia. 10 stations located in major cities across Indonesia are measuring in real-time PM<sub>10</sub> pollution. </p> <p> The monitoring stations are operated by <a href='http://bmkg.go.id'>BMKG</a> (<i>Badan Meteorologi Klimatologi dan Geofisika</i>), the Indonesian Department of Meteorology, Climatology and Geophysics. </p> <center><a href='https://aqicn.org/faq/2015-07-18/real-time-air-quality-monitoring-in-indonesia/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-07-16/air-quality-scale-in-quebec-and-montreal/' class='faqlisttitle'>Air Quality Scale in Quebec and Montreal</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>July 16<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-07-16/air-quality-scale-in-quebec-and-montreal/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-07-16/air-quality-scale-in-quebec-and-montreal/"'> <style> table.fancy { border: 2px solid black; border-spacing: 0px; background: white; } table.fancy td { margin: 0px; padding: 3px; text-align: center; border-bottom: solid 1px #DEDEDE; border-right: solid 1px #DEDEDE; font-size: 13px; } table.fancy tr:hover { background: #9AC9FF; } </style> <div style='float:right;padding-left:20px;text-align:center;'> <img alt="Flag of Quebec.svg" src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Flag_of_Quebec.svg/225px-Flag_of_Quebec.svg.png" width="225" height="150" class="thumbborder" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Flag_of_Quebec.svg/338px-Flag_of_Quebec.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Flag_of_Quebec.svg/450px-Flag_of_Quebec.svg.png 2x" data-file-width="600" data-file-height="400"> <br> <small> The <i>Fleurdelisé</i>, flag of Quebec.<br> (attribution: <a href='https://en.wikipedia.org/wiki/Flag_of_Quebec'>wikipedia</a>) </small> </div> <p class="bigletter"> The Air Quality data for <a href='/city/montreal/'>Montreal</a> and <a href='/map/quebec/'>Quebec</a> has been available for a while, but we recently got few questions about the AQI scale used in this part of Canada. One of them is from Marie A., who asked: </p> <blockquote> <p> I would like to know why the Air Quality Index on your web site is different from the AQI on the Montreal's website? Do you recalculate anything to meet the US EPA AQI standards? If so, how? With what data? </p> </blockquote> <p> This is indeed a very good question. and we will explain in this article the different scales in use, how the scales compare to each other, and how the convertion can be done. </p> <br><br> <center><a href='https://aqicn.org/faq/2015-07-16/air-quality-scale-in-quebec-and-montreal/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-07-01/translation-for-polish-is-now-available/' class='faqlisttitle'>Translation for Polish is now available</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>July 1<sup>st</sup> 2015</small><div><small>https://aqicn.org/faq/2015-07-01/translation-for-polish-is-now-available/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-07-01/translation-for-polish-is-now-available/"'> <div style='float:right;padding-left:10px;'> <img border=1 alt="Flag of Poland.svg" src="//upload.wikimedia.org/wikipedia/en/thumb/1/12/Flag_of_Poland.svg/240px-Flag_of_Poland.svg.png" width="240" height="150" class="thumbborder" srcset="//upload.wikimedia.org/wikipedia/en/thumb/1/12/Flag_of_Poland.svg/360px-Flag_of_Poland.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/1/12/Flag_of_Poland.svg/480px-Flag_of_Poland.svg.png 2x" data-file-width="1280" data-file-height="800"> <br> <center> <small> Flag of the Republic of Poland <br> (attribution: <a href='https://en.wikipedia.org/wiki/Flag_of_Poland'>wikipedia</a>) </small> </center> </div> <p class='bigletter'> Thanks to the <a href='/home/'>World Air Quality Index</a> project community, translations for the <a href='https://en.wikipedia.org/wiki/Polish_language'>Polish language</a> are now available for the Website and web-application. Many thanks especillay to the user "<i>AiRs</i>" for the excellent contribution. </p> <center><a href='https://aqicn.org/faq/2015-07-01/translation-for-polish-is-now-available/' class='faq-read-more'>Read the full article</a></center><br><br> <div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-06-08/wind-and-air-pollution-forecast-in-quito/' class='faqlisttitle'>Wind and Air Pollution Forecast in Quito</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>June 8<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-06-08/wind-and-air-pollution-forecast-in-quito/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-06-08/wind-and-air-pollution-forecast-in-quito/"'> <div style='float:right;padding-left:10px;border:0px solid black;'> <center> <img src='/images/wind-in-ecuador/guagua.jpg'> <br> <small> Guagua Pichincha volcano in Ecuador (<a href='http://naturegalapagos.blogspot.com/2013/11/ecuador-volcanoes.html'>Attribution</a>) </small> </center> </div> <p class='bigletter'> Beijing citizens do know for long that the best natural way to clean the pollution in the air is strong winds from the North, while winds from the south might, on the contrary, bring more pollution from Hebei. </p> <p> In <a href='http://www.quito.com.ec/en'>Quito</a>, Ecuador, there is a similar problematic, except that the pollution comes from the active <a href='http://en.wikipedia.org/wiki/List_of_volcanoes_in_Ecuador'>volcanos</a>. Fortunately, they do not erupt that often, but when they erupt, better avoid being under the the heavy <a href='http://en.wikipedia.org/wiki/Volcanic_ash'>ash cloud</a> formed by the explosive eruptions (see picture). </p> <center><a href='https://aqicn.org/faq/2015-06-08/wind-and-air-pollution-forecast-in-quito/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-06-03/overview-of-hong-kongs-air-quality-health-index/' class='faqlisttitle'>Overview of Hong Kong's Air Quality Health Index</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>June 3<sup>rd</sup> 2015</small><div><small>https://aqicn.org/faq/2015-06-03/overview-of-hong-kongs-air-quality-health-index/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-06-03/overview-of-hong-kongs-air-quality-health-index/"'> <div style='float:right;padding-left:10px;'> <img src='/images/aqi-scales/AQHI-logo.png'> </div> <p class='bigletter'> It is already a long time since the Hong Kong EPA has updated its Air Quality Index standard from the traditional <i>Air Pollution Index</i> to the so called <i>Air Quality <u>Health</u> Index</i> (AQHI), but we never got a change until now to have a deeper look at it, which we will do in this article. </p> <p>The Hong Kong EPA has actually done an excellent work at explaining how the AQHI is defined, and the information one needs to understand the AQHI is available from their <a href='http://www.aqhi.gov.hk/en/what-is-aqhi/faqs.html'>website</a>. The most obvious simplification is the change of the traditional 0-500 index into a new simplifed 0-10<sup>+</sup> range, sub-divded in five health risk categories, as shown below: </p> <center> <style type="text/css"> @media only screen and (max-width: 920px) { .aqih-scale-table { font-size: 10px; } } </style> <table class='aqih-scale-table'> <tr style='text-align:center;'> <td colspan=3>LOW <td colspan=3>MODERATE <td colspan=1>HIGH <td colspan=3>VERY HIGH <td colspan=1>SERIOUS <tr> <td colspan=3 width=20%> <div style='background-color:#4db748;width:100%;height:10px;'> <td colspan=3 width=20%> <div style='background-color:#f9a61a;width:100%;height:10px;'> <td colspan=1 width=20%> <div style='background-color:#ed1b24;width:100%;height:10px;'> <td colspan=3 width=20%> <div style='background-color:#a04623;width:100%;height:10px;'> <td colspan=1 width=20%> <div style='background-color:#000000;width:100%;height:10px;'> <tr style='text-align:center;'> <td>1 <td>2 <td>3 <td>4 <td>5 <td>6 <td>7 <td>8 <td>9 <td>10 <td>10+ </table> </center> <p> But there is actually much more than a range simplification: the new AQHI is also introducing the very clever concept of Added Health Risk <i>(%AR)</i>, which was originally <a href='http://www.ehrn.co.za/publications/download/04.pdf'>defined</a>, in 2007, by a team of four partners from South Africa, and first used in <a href='http://www.publichealthontario.ca/en/eRepository/Air_Quality_Indeces_Report_2013.pdf'>Canada</a>. </p> <br> <center><a href='https://aqicn.org/faq/2015-06-03/overview-of-hong-kongs-air-quality-health-index/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-05-30/air-quality-forecast-in-south-america/' class='faqlisttitle'>Air Quality Forecast in South America</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>May 30<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-05-30/air-quality-forecast-in-south-america/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-05-30/air-quality-forecast-in-south-america/"'> <p> The Air Quality forecast for South America is now available on the <a href='/home//'>World Air Quality Index project</a>, in parnership with the Brazilian <i>Centro de Previsão do Tempo e Estudos Climáticos (<a href='http://www.cptec.inpe.br/home/in'>CPTEC</a>)</i>. The forecast can be accessed freely accessed from <a href='http://meioambiente.cptec.inpe.br'>cptec.inpe.br</a> as well as <a href='/forecast/south-america/'>forecast/ south-america/</a>. </p> <p> The CPTEC team has done an excellent work at providing a simple and detailed <a href='http://meioambiente.cptec.inpe.br/modelo_cattbrams.php?lang=en'>explanation</a> on the underlying concepts used by their forecast model, called <a href='http://brams.cptec.inpe.br/'>BRAMS</a> (for <i> Brazilian developments on the Regional Atmospheric Modelling System</i>). The picture below (from the CPTEC) is giving an insight on the workflow for their model (source -> transport -> deposition). </p> <br> <center> <img src='/images/forecast/catt_brams_3d_model_grid_box.jpg' style='width:500px;max-width:90%'> </center> <br> <br> <center><a href='https://aqicn.org/faq/2015-05-30/air-quality-forecast-in-south-america/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-05-18/ground-ozone-air-quality-index-update-with-instant-cast/' class='faqlisttitle'>Ground Ozone Air Quality Index update with Instant Cast</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>May 18<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-05-18/ground-ozone-air-quality-index-update-with-instant-cast/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-05-18/ground-ozone-air-quality-index-update-with-instant-cast/"'> <div style='float:right;padding-left:10px;border:0px solid black;'> <center> <img src="/images/ozone-units/good-and-bad-ozone.png" width=450> <br> <small> <small><small>(Attribution: <a href='http://houstoncleanairnetwork.com/what-is-ozone'> Houston Clean Air Network</a> )</small></small> </small> </center> </div> <p class='bigletter'> The ground Ozone Air Quality Index calculation has just been updated to follow the Instant Cast concept, i.e. to report the pollution right now instead of the pollution from the previous hours. For more information about the Instant Cast, please refer to this <a href='/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/'>article</a>. </p> <p> The calculation for the Ozone Index is now using the hourly reading, instead of the previous 8 hours average, but still applying the same 8 hours AQI breakpoints formula for AQI below 100. The previous <a href='http://www.arb.ca.gov/regact/area06/appe.pdf'>procedure</a> for calculating the 8-hour average concentrations is not used any more for Instant reporting. Above AQI 100, the normal 1 hour Ozone breakpoints are used (while before, the AQI above 100 was defined as the maximum of the 1 hour and 8 hours readings). </p> <br> <br><center><a href='https://aqicn.org/faq/2015-05-18/ground-ozone-air-quality-index-update-with-instant-cast/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-05-16/world-health-organization-2014-air-pollution-ranking/' class='faqlisttitle'>World Health Organization: 2014 Air Pollution Ranking</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>May 16<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-05-16/world-health-organization-2014-air-pollution-ranking/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-05-16/world-health-organization-2014-air-pollution-ranking/"'> <div style='float:right;padding-left:10px;border:0px solid black;' > <center> <img src='/air/view/faq/images/unep/who-150x150.png' title='World Health Organization'> </center> </div> <p class='bigletter'> It is already more than one year since the World Health Organization has released their '<a href='http://www.who.int/phe/health_topics/outdoorair/databases/cities/en/'>Ambient (outdoor) air pollution in cities</a> database 2014'. The WHO team who worked on this project have done an excellent work at gathering the data for so many countries, and putting it all together in a single place accessible for all. </p> <p> We wrote about it in several of our past articles (like for the Air Quality <a href='/faq/2015-04-08/air-quality-in-africa-and-middle-east/'> in Africa</a> or in <a href='/faq/2015-05-10/a-comparison-of-latin-american-air-quality-scales/'>Latin America</a>), but we never had the chance to look at the different options to visualize their data set. So, this is what we will be writing about in this article. </p> <center><a href='https://aqicn.org/faq/2015-05-16/world-health-organization-2014-air-pollution-ranking/' class='faq-read-more'>Read the full article</a></center><br><br> <div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-05-15/india-national-air-quality-index/' class='faqlisttitle'>Overview of India's National Air Quality Index</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>May 15<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-05-15/india-national-air-quality-index/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-05-15/india-national-air-quality-index/"'> <div style='float:right;padding-left:10px;border:0px solid black;'> <center> <small> <div class='img-thumbnail flag flag-icon-background flag-icon-in' style='width:250px;height:150px;'></div> Flag of India<br><small>(Tiranga, तिरंगा)</small> </small> </div> <link rel='stylesheet' href='/images/flags.css/css/flag-icon.min.css' /> <p class='bigletter'> The Indian Central Pollution Control Board has recently announced, in April 2015, the publication of India's National Air Quality Index Standard (<i>NAQI </i>). All the details on this standard are available from <a href='http://www.cpcb.nic.in/AQI_new.php'>CPCB</a>, <a href='http://en.wikipedia.org/wiki/Air_quality_index#India'>wikipedia</a> or from this <a href='/images/aqi-scales/india-national-air-quality-standard.pdf'>report</a> from Indian Institute of Technology, Kanpur (<a href='http://iitk.ac.in'>iitk.ac.in</a>). </p> <p> This is actually a very important step forward in the Air Quality world awarness, since the air pollution in each country is very much specific to the country pollution type: For instance because of Dust (in Arabic Peninsula), because of Transport (New Delhi) or topography (Chile). </p> <center><a href='https://aqicn.org/faq/2015-05-15/india-national-air-quality-index/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-05-10/a-comparison-of-latin-american-air-quality-scales/' class='faqlisttitle'>A comparison of Latin American Air Quality Scales</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>May 10<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-05-10/a-comparison-of-latin-american-air-quality-scales/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-05-10/a-comparison-of-latin-american-air-quality-scales/"'> <link rel='stylesheet' href='/air-static/view/images/flags.css/css/flag-icon.min.css' /> <div style='float:right;padding-left:10px;'> <img src='/air-static/view/faq/images/aqi-scales/oms-latin-america.png'> </div> <p class='bigletter'> Latin America, just like any other continent in our world is facing Air Pollution. The recent 2014 report by the <a href='http://www.who.int/phe/health_topics/outdoorair/databases/cities/en/'>World Health Organization</a> on Ambient (outdoor) Air Pollution gives some annual mean figures for several cities in Latin America. Without surprise, the worst scenarios are in Asia, but yet, some cities in Latin America have high indexes too (see table on the left). </p> <p>The ranking from the WHO should however by considered carefully, especially considering the measurement methods used the report can be argued - for instance, for Lima, the Peruvian EPA is arguing that the data from the WHO is not correct because the samples were not taken in the right places (read this article from <a href='https://ksj.mit.edu/tracker/2014/05/who-releases-database-about-air-pollutio/'>P. Estupinya</a> for full feedback from several countries). This is actually for this reason that we only publish real-time information on the <a href='/home/'>World Air Quality project</a> since we do believe than more than ranking, it is the current conditions that are important for the world citizen. </p> <br><br> <center><a href='https://aqicn.org/faq/2015-05-10/a-comparison-of-latin-american-air-quality-scales/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-05-02/south-asian-air-quality-scales-malaysia-and-thailand/' class='faqlisttitle'>South Asian Air Quality Scales: Malaysia and Thailand</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>May 2<sup>nd</sup> 2015</small><div><small>https://aqicn.org/faq/2015-05-02/south-asian-air-quality-scales-malaysia-and-thailand/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-05-02/south-asian-air-quality-scales-malaysia-and-thailand/"'> <link rel='stylesheet' href='/images/flags.css/css/flag-icon.min.css' /> <div style='float:right;padding-left:10px;'> <center> <small> <div class='img-thumbnail flag flag-icon-background flag-icon-my' style='width:250px;height:150px;'></div> Flag of Malaysia<br><small>(Jalur Gemilang)</small> </small> </div> <p class='bigletter'> Air Quality for Malaysia has been available for a long time, but unlike other countries, only the composite AQI is provided. The AQI for the individual pollutants such as PM<sub>10</sub>, Ozone ... is not available, which makes the convertion to the US EPA scale more difficult. </p> <p> Fortunately, the information about the AQI scale used in Malaysia, also known as API (for Air Pollutant Index) is clearly explained in the document '<a href='/images/aqi-scales/malaysia-api-guide.pdf'>A guide to Air Pollutant Index in Malaysia</a>'. </p> <br> <br> <center><a href='https://aqicn.org/faq/2015-05-02/south-asian-air-quality-scales-malaysia-and-thailand/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-04-28/real-time-air-quality-in-the-balkan-peninsula/' class='faqlisttitle'>Real-time Air Quality in the Balkan Peninsula</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>April 28<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-04-28/real-time-air-quality-in-the-balkan-peninsula/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-04-28/real-time-air-quality-in-the-balkan-peninsula/"'><link rel='stylesheet' href='/images/flags.css/css/flag-icon.min.css' /> <a href='https://aqicn.org/faq/2015-04-28/real-time-air-quality-in-the-balkan-peninsula/'> <div style='float:right;padding-left:10px;margin-left:10px;'> <img width="300" alt="Balkan peninsula line" src="//upload.wikimedia.org/wikipedia/commons/c/cf/Balkan_peninsula_line.jpg" /> </a> </div> <p> The Balkan Peninsula, popularly referred to as the Balkans, is a geographical region of Southeast Europe. The region takes its name from the Balkan Mountains that stretch from the east of Serbia to the Black Sea at the east of Bulgaria. </p> <p> Many of the countries in the Balkans are providing real-time Air Quality readings. The data for <a href='/map/turkey/'>Turkey</a> (Thrace), <a href='/map/romania/'>Romania</a> and <a href='/map/croatia/'>Croatia</a> have already been available on the World Air Quality Index project for a long time. Today, we are able to roll-out the data for 3 new countries: <a href='/map/serbia/'>Serbia</a>, <a href='/map/bulgaria/'>Bulgaria</a> and <a href='/map/macedonia/'>Macedonia</a>. </p> <br> <br> <center><a href='https://aqicn.org/faq/2015-04-28/real-time-air-quality-in-the-balkan-peninsula/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-04-26/nasa-earth-observations-and-tools-for-air-quality-applications/' class='faqlisttitle'>NASA - Earth Observations and Tools for Air Quality Applications</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>April 26<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-04-26/nasa-earth-observations-and-tools-for-air-quality-applications/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-04-26/nasa-earth-observations-and-tools-for-air-quality-applications/"'> <div style='float:right;padding-left:10px;margin-left:10px;max-width: 50%;width:300px;' > <a href='https://aqicn.org/faq/2015-04-26/nasa-earth-observations-and-tools-for-air-quality-applications/'> <img width="250" style='max-width: 100%;' alt="The Earth seen from Apollo 17 with transparent background" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/43/The_Earth_seen_from_Apollo_17_with_transparent_background.png/512px-The_Earth_seen_from_Apollo_17_with_transparent_background.png"/> </a> </div> <p class='bigletter'> We had the honor to be invited by <a href='http://science.gsfc.nasa.gov/sed/index.cfm?fuseAction=people.jumpBio&iphonebookid=27549'>Dr Pawan Gupta</a> from the NASA Applied Remote Sensing Training (<a href='http://arset.gsfc.nasa.gov/'>ARSET</a>) team to give a presentation about our <a href='/home/'>World Air Quality Index</a> project at the Earth Observations and Tools for Air Quality Applications webinar: </p> <br><center><a href='https://aqicn.org/faq/2015-04-26/nasa-earth-observations-and-tools-for-air-quality-applications/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-04-08/air-quality-in-africa-and-middle-east/' class='faqlisttitle'>Air Quality in Africa and Middle East</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>April 8<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-04-08/air-quality-in-africa-and-middle-east/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-04-08/air-quality-in-africa-and-middle-east/"'> <style type="text/css"> .calculatornoteref { background-color: orange; color: white; border: 1px solid #888; min-width: 12px; text-align: center; font-size: 10px; display: inline-block; border-radius: 5px; -moz-border-radius: 5px; -webkit-border-radius: 5px; -box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -webkit-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); } .aqisnapshot { -box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -webkit-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); margin: 3px; } </style> <div style='float:right;padding-left:10px;border:0px solid black;max-width: 50%;width:330px;'> <center> <img src='/air/view/faq/images/unep/african_union_flag.png' style='width: 100%;'> <br> <br> <a href='http://en.wikipedia.org/wiki/Flag_of_the_African_Union'>Flag of the African Union</a> </center> </a> </small> </div> <p> When talking about Air Quality, the first countries that comes to people's mind are China and India, and more generally Asia. Even on the <a href='/home/'>World Air Quality Index project</a>, Asia has always been, since the begining, our strong focus (most likely because this is where our HQ is located!). </p> <p> Few years ago, in 2012, we decided to extend our scope to cover the other <a href='http://www.nationsonline.org/oneworld/continents.htm'>seven continents</a>, starting with <a href='/map/australia/'>Oceania</a>, and then following with <a href='/map/australia/'>Europe</a> and <a href='/map/northamericas/'>North America</a>, <a href='/map/southamericas/'>South America</a>. </p> <p> But one of seven continents, namely <i>Africa</i>, has been surprisingly lacking behind. We received many inquiries about this lack of data, and one of the last was from Said E. who wrote: </p> <blockquote> <p> Thanks for making the World Air Quality Index project site. It gives very useful information.<br> My only concern is why <b>Africa</b> is not considered.<br> For information I am a moroccan citizen.<br> </p> </blockquote> <br><center><a href='https://aqicn.org/faq/2015-04-08/air-quality-in-africa-and-middle-east/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-03-23/air-quality-forecasting-how-accurate-can-it-be/' class='faqlisttitle'>Air Quality Forecasting - How accurate can it be?</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>March 23<sup>rd</sup> 2015</small><div><small>https://aqicn.org/faq/2015-03-23/air-quality-forecasting-how-accurate-can-it-be/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-03-23/air-quality-forecasting-how-accurate-can-it-be/"'> <style type="text/css"> .forecastgraphin { padding: 5px; margin-bottom: 5px; border: 1px solid #aaa; background-color: #eeeeee; -box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2); -moz-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2); -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2); } .forecastgraph { font-size: 15px; display: inline-block; width: 100%; padding: 0px; text-align: left; color: #888888; margin-left: 10px; margin-right: 10px; } .graphtitle { text-shadow: 1px 1px 0 white; font-size: 18px; min-width: 300px; margin: 0px; height: 8px; color: black; border-bottom: 0px solid black; } .forecast-country { font-size: 28px; height: 40px; } .hline { stroke-width: .3; stroke: #ffffff; } .hmline { shape-rendering: crispEdges; stroke-width: 1px; stroke: #cccccc; } .vline { stroke: #cccccc; shape-rendering: crispEdges; stroke-width: 1px; xstroke-dasharray: 2, 3; } .vlinetext { font-size: 10px; } .rect { stroke: #ffffff; stroke-width: 1; } .hlinetext { background-color: yellow; font-size: 10px; } #forecastdiv {} .aqiv { border: 1px solid #888; background-color: white; border-radius: 2px; -moz-border-radius: 2px; -webkit-border-radius: 2px; -box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2); -moz-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2); -webkit-box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2); } .axis path, .axis line { fill: none; stroke: #ccc; stroke-width: 1px; shape-rendering: crispEdges; } .axis text {} button { background-color: #4ebb44; border: none; font-family: "dropplets"; color: #ffffff; text-align: center; width: 70px; font-size: 20px; padding: 5px; cursor: pointer; -moz-transition-duration: 0.1s; -webkit-transition-duration: 0.1s; } button:hover { box-shadow: inset 0 0 20px rgba(54, 124, 49, 0.75); text-shadow: 0 0 10px rgba(54, 124, 49, 0.75); } </style> <div style='float:right;padding-left:10px;border:0px solid black;border-left:1px dashed #ccc;margin-left:10px;max-width: 50%;width:380px;'> <div style='color:#888;font-size:12px;line-height:1.5;text-align: center;'> <img src='/images/forecast/wind-looping.jpg' style='width:100%' title='Atmospheric Stability - STRONG LAPSE CONDITION (LOOPING)'> <br> STRONG LAPSE CONDITION (LOOPING) <br> <img src='/images/forecast/wind-coning.jpg' style='width:100%' title='Atmospheric Stability - WEAK LAPSE CONDITION (CONING)'> <br> WEAK LAPSE CONDITION (CONING) <br> <img src='/images/forecast/wind-fanning.jpg' style='width:100%' title='Atmospheric Stability - INVERSION CONDITION (FANNING)'> <br> INVERSION CONDITION (FANNING) <br> <br> Examples of Atmospheric Stability (<a href='https://courses.ecampus.oregonstate.edu/ne581/eleven/'>attribution</a>) </div> </div> <p> In weather prediction, forecast models are used to predict future states of the atmosphere, based on how the climate system evolves with time from an initial state. </p> <p> While the forecast models are quite <a href='http://en.wikipedia.org/wiki/Meteorological_reanalysis'>complex</a> (and <i>do</i> require strong scientific and engineering capabilities), the science of analyzing those forecast models, and verifying their <a href='http://en.wikipedia.org/wiki/Forecasting#Forecasting_accuracy'>accuracy</a>, by comparing actual empirical observations to predicted values, is quite straightforward. </p>  <p> For the domain of Air Quality, just like for weather prediction, it is possible to define models used to predict the future set of atmospheric pollution. There are actually <a href='http://pandora.meng.auth.gr/mds/strquery.php?wholedb'>plenty of such models</a>, often referred as <a href='http://en.wikipedia.org/wiki/Atmospheric_dispersion_modeling'>Atmospheric Dispersion Modeling</a>. And just like weather prediction, the same concept of accuracy analysis can be applied to Atmospheric pollution predictions. </p> <br><center><a href='https://aqicn.org/faq/2015-03-23/air-quality-forecasting-how-accurate-can-it-be/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-03-20/a-comparison-of-worldwide-air-quality-scales-part-1/' class='faqlisttitle'>A comparison of worldwide Air Quality Scales - Part 1</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>March 20<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-03-20/a-comparison-of-worldwide-air-quality-scales-part-1/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-03-20/a-comparison-of-worldwide-air-quality-scales-part-1/"'> <style type="text/css"> .calculatornoteref { background-color: orange; color: white; border: 1px solid #888; min-width: 12px; text-align: center; font-size: 10px; display: inline-block; border-radius: 5px; -moz-border-radius: 5px; -webkit-border-radius: 5px; -box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -webkit-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); } .aqisnapshot { -box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -moz-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); -webkit-box-shadow: 1px 1px 2px rgba(0, 0, 0, 0.5); margin: 3px; } </style> <div style='float:right;padding-left:10px;border:0px solid black;'> <center> <a href='http://who.int' target=_who> <img src='/images/aqi-scales/who-logo.jpg' width=250 title='World Health Organization'> <br> <span style='font-size:12px;color:#888;'>World Health Organization</span><br><br></center> </a> </small> </div> <p> Very often we receive inquiries from users asking about the numbers published on the <a href='/home/'>World Air Quality Index project</a>, and wondering about the difference with the values expressed in other websites. And that's actually normal, since the numbers, also called Air Quality Indexes (AQI), can be very confusing for beginners. The last message we received is the following one: </p> <blockquote> <p> We have been checking air quality index for the Tianjin, China since last year, however we found the data has such a big difference between your website and another official (air.tjemc.org.cn) one which is stated on yours as well. I am wondering which one can provide more accurate data, as it will affect the decision for outdoor or indoor. Please help me with this issue. Thank you! </p> </blockquote> <p> We have been writing quite a lot about this issue before, for instance from <a href='/faq/2013-01-19/shanghai-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shanghai/'> <i>a comparative PM<sub>2.5</sub> data for shanghai</i></a>, <a href='/faq/2013-06-25/singapore-psi-and-pm25-aqi-why-is-there-a-difference-between-the-two-readings/'> <i>singapore PSI and PM<sub>2.5</sub> AQI</i></a> and more recently about the <a href='/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/'> <i>nowcast</i></a>. </p> <p> But, because we are still getting many questions, we are now writing this article to explain the difference of the AQI scales used all over the world. </p> <br> <br> <center><a href='https://aqicn.org/faq/2015-03-20/a-comparison-of-worldwide-air-quality-scales-part-1/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/' class='faqlisttitle'>A Beginner's Guide to Air Quality Instant-Cast and Now-Cast. </a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>March 15<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/"'> <div style='float:right;padding-left:10px;'> <img src='/images/nowcast/typhoon-asia-2004293.jpg' width=280> <br> </div> <p> Back in March 2015, we had the chance to meet in Beijing several environmental specialists from the US State Department as well as the China Mission (<i>the famous entity running the PM<sub>2.5</sub> monitors in the Beijing US embassy</i>). </p> <p> Among all the topics that were addressed, there is one worth writing about, namely the "<i><b>nowcast</b></i>" system. This system used by the US EPA to convert the raw pollutants readings, expressed in µg/m3 or<i> ppb</i>, into the AQI (scale from 0 to 500). It is used for all the AQI values reported on the <a href='http://airnow.gov'>airnow.gov</a> website. </p> <p> The concept behind the <i>nowcast</i> is to compensate the "<i>24 hours averaging</i>", which should be used when converting concentrations to AQI. The reason for this averaging is that the <a href='http://airnow.gov/index.cfm?action=aqibasics.aqi'>AQI scale</a> specifies that each of the Levels of Health Concern (i.e. Good, Moderate,... Unhealthy...) is valid under a 24 hours exposure<sup><a href="#nowcast-footnote-1">[1]</a></sup>. For example, when seeing a 188 AQI (Unhealthy), one need to read it as "<i style='color:#888;'>if I stay out for 24 hours, and the AQI is 188 <span style='color:#cc0033;'>during those 24 hours</span>, then the health effect is Unhealthy</i>". This is quite different from saying that "<i style='color:#888;'>if the AQI reported now is 188, then the health effect is Unhealthy</i>". </p> <center><a href='https://aqicn.org/faq/2015-03-15/air-quality-nowcast-a-beginners-guide/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-02-23/south-asia-real-time-air-quality-monitoring-project/' class='faqlisttitle'>South Asia Real-time Air Quality Monitoring Project</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>February 23<sup>rd</sup> 2015</small><div><small>https://aqicn.org/faq/2015-02-23/south-asia-real-time-air-quality-monitoring-project/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-02-23/south-asia-real-time-air-quality-monitoring-project/"'> <div style='float:right;padding-left:10px;margin-bottom:20px;'> <img src='/images/manilla/goat-chunjie-2015.jpg'> <br> </div> <p> We have just stepped in the Lunar New Year of the Goat (combined with the <i>Wood</i> element for 2015), and, for the World Air Quality Index project team, that means full speed working on extending the Air Quality monitoring to new countries in South East Asia. Namely: <a href='/country/philippines/'><b>The Philippines</b></a>, <a href='/country/cambodia/'><b>Cambodia</b></a> and <a href='/country/indonesia/'><b>Indonesia</b></a> (and more, e.g. Myanmar and Laos, will follow very soon). </p> <p> As there is also a huge demand for PM<sub>2.5</sub> monitoring for <a href='/country/thailand/'><b>Thailand</b></a> (especially Chiang Mai and Bangkok), or for more station in <a href='/map/vietnam/'><b>Vietnam</b></a> (Ho Chi Minh City), the extension will also cover selected countries with existing network. </p> <p> But, this time, unlike for the previous countries, we do need the help of everyone, and especially <b>your help</b> if you are living in one of those countries. The reason is that, this time, since the real-time Air Quality information is not publicly available from the Environmental Protection Agencies (EPA) of those countries, the World Air Quality Index project will start to crowdsource Air Quality monitoring stations in the main cities of the above countries<sup><a href="#notes" id="ref1">1</a></sup>. </p> <img src='/images/manilla/manilla-jakarta-skyline.jpg' width=100%><br> <i><small>Visible Air Pollution on the Manilla and Jakarta Skylines</small></i> <br><center><a href='https://aqicn.org/faq/2015-02-23/south-asia-real-time-air-quality-monitoring-project/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2015-02-15/satellite-air-quality-monitoring-introduction-to-the-nasa-worldview/' class='faqlisttitle'>Satellite Air Quality monitoring: Introduction to the NASA WorldView</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>February 15<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-02-15/satellite-air-quality-monitoring-introduction-to-the-nasa-worldview/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-02-15/satellite-air-quality-monitoring-introduction-to-the-nasa-worldview/"'> <p> We recentely had the privilege to start a cooperation with the <a href='http://arset.gsfc.nasa.gov'>NASA Remote Sensing monitoring program</a>.; </p> <p> The objective is to use the Remote Air Quality sensing based on the NASA Satelites to determine the Air Quality in areas where sensors are not available (e.g. over the sea, but also for countries where sensors are not yet available). </p> <br> <br> <center><a href='https://aqicn.org/faq/2015-02-15/satellite-air-quality-monitoring-introduction-to-the-nasa-worldview/' class='faq-read-more'>Read the full article</a></center><br><br> <center> <a href='https://aqicn.org/faq/2015-02-15/satellite-air-quality-monitoring-introduction-to-the-nasa-worldview/'> <img src='/images/nasa-earthview/earthview-asia-hotspots-2015.01.14.small.jpg' width=100%> </a> <br> <br> <a href='https://aqicn.org/faq/2015-02-15/satellite-air-quality-monitoring-introduction-to-the-nasa-worldview/'> <img src='/images/nasa-earthview/earthview-asia-aod-panel-2015.01.25-small.jpg' width=100%> </a> <br> </center> <div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2015-02-08/visual-recognising-the-air-quality-index-a-case-applied-to-hanoi/' class='faqlisttitle'>Visual recognising the Air Quality Index - a case applied to Hanoi</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>February 8<sup>th</sup> 2015</small><div><small>https://aqicn.org/faq/2015-02-08/visual-recognising-the-air-quality-index-a-case-applied-to-hanoi/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2015-02-08/visual-recognising-the-air-quality-index-a-case-applied-to-hanoi/"'> <p> Earlier this week (of February 2015), we got several inquries from Hanoi citizen wondering about the Air Quality Index which was displayed on the Hanoi page (<a href='/city/vietnam/hanoi/'>city/vietnam/hanoi</a>). </p> <p> The main reason for the inquiry was that the Air Quality Index displayed on the World Air Quality Index project was around 50 (green AQI) level, while the outdoor visibilty in Hanoi looked like this: </p> <center> <img src='/images/hanoi-aqi/Hanoi.10Feb.13.30-small.jpg' width=100%> </center> <br> <center><a href='https://aqicn.org/faq/2015-02-08/visual-recognising-the-air-quality-index-a-case-applied-to-hanoi/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2014-10-28/android-app-update-now-with-embedded-map-and-wind-forecast/' class='faqlisttitle'>Android app. update: now with embedded map and wind forecast.</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>October 28<sup>th</sup> 2014</small><div><small>https://aqicn.org/faq/2014-10-28/android-app-update-now-with-embedded-map-and-wind-forecast/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2014-10-28/android-app-update-now-with-embedded-map-and-wind-forecast/"'><style type="text/css"> img.androidthumbnail3 { width:150px; height:280px; border:1px solid #888; padding:1px; } .thumbnailcrop3 { height: 270px; overflow: hidden; display: inline-block; margin:5px; border-bottom:1px solid #888; xfont-style:italic; color:#888; } .picletsharing { -box-shadow: 1px 1px 2px rgba(0,0,0,0.5); -moz-box-shadow: 1px 1px 2px rgba(0,0,0,0.5); -webkit-box-shadow: 1px 1px 2px rgba(0,0,0,0.5); margin:3px; } </style> <p> The latest version 3.2 of the World Air Quality Index project Android application has just been released, and comes with few new cool features: </p> <p> The embedded <b>map</b> which will let you navigate through the world air monitoring station directly from the app and the <b>wind</b> and temperature <b>forecast</b> tab which gives you the coming 3 days forecast. We have also been working on refreshing the visual and updating settings to support, for instance, Fahrenheit temperature display. </p> <center> <small> You can get the app from the <a href='https://play.google.com/store/apps/details?id=com.insdio.aqicn.airwidget.Asia' target=_googlestore>google store</a>, or directly download the <a href='/?apk'>signed apk</a> from our website, in case you do not have access the Android app store.<br> </small> </center> <br> <br> <center> <div class='thumbnailcrop3'>Station map<br>(Asia)<br><img src='/air//view/faq/images/app-3.2/small/map0.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>Station map<br>(North China)<br><img src='/air//view/faq/images/app-3.2/small/map1.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>Station map<br>(Beijing)<br><img src='/air//view/faq/images/app-3.2/small/map2.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>Station map<br>(Seoul)<br><img src='/air//view/faq/images/app-3.2/small/map3.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>Wind and Temperature<br>Forecast<br><img src='/air//view/faq/images/app-3.2/small/forecast.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>Improved Settings<br><img src='/air//view/faq/images/app-3.2/small/settings.en.png' class='androidthumbnail3'></div><br><div class='thumbnailcrop3'>Pollutant graphs<br>and wind conditions<br><img src='/air//view/faq/images/app-3.2/small/graph.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>Homescreen<br>Widgets<br><img src='/air//view/faq/images/app-3.2/small/home.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>Notifications<br>when AQI > 150<br><img src='/air//view/faq/images/app-3.2/small/notification.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>AQI Information for<br>the nearest stations<br><img src='/air//view/faq/images/app-3.2/small/nearest.en.png' class='androidthumbnail3'></div><div class='thumbnailcrop3'>AQI Levels<br>Explanations<br><img src='/air//view/faq/images/app-3.2/small/levels.en.png' class='androidthumbnail3'></div></center> <br> <br><center><a href='https://aqicn.org/faq/2014-10-28/android-app-update-now-with-embedded-map-and-wind-forecast/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2014-10-06/clean-air-initiative-and-the-better-air-quality-conference-2014/' class='faqlisttitle'>Clean Air Initiative and the Better Air Quality Conference 2014</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>October 6<sup>th</sup> 2014</small><div><small>https://aqicn.org/faq/2014-10-06/clean-air-initiative-and-the-better-air-quality-conference-2014/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2014-10-06/clean-air-initiative-and-the-better-air-quality-conference-2014/"'> <p> Like every other year since 2002, our collegues from <a href='http://cleanairasia.org/' target="_blank">Clean Air Asia</a> (aka Clean Air Initiative) are organiznig the biennial <a href='http://baq2014est.org/'>Better Quality Conference</a> (<a href='http://baq2014est.org/' target="_blank">baq2014est.org</a>). This time, it will take place in Sri Lanka, from November 19th to 21st 2014, and will be co-hosted together with the <i>Environmentally Sustainable Transport</i> (EST) forum. </p> <div style='float:right;padding-left:20px;text-align:center;margin-top:-38px;'> <img src='/images/baq-2014-logo.png' > </div> <blockquote style='color:#444'> The "Integrated Conference of BAQ 2014 and Intergovernmental 8th Regional EST Forum in Asia"  co-organized by the <a href="http://www.transport.gov.lk/web/index.php?lang=en">Ministry of Transport of Sri Lanka</a>, <a href="http://www.environmentmin.gov.lk/web/">The Ministry of Environment and Renewable Energy of Sri Lanka</a>, <a href="http://www.env.go.jp/en/" target="_blank">Ministry of the Environment of Japan</a>, <a href="http://www.uncrd.or.jp/" target="_blank">United Nations Centre for Regional Development</a>, and <a href="http://www.cleanairasia.org" target="_blank">Clean Air Asia</a>, in partnership with the <a href="http://www.adb.org/" target="_blank">Asian Development Bank</a>, <a href="http://www.giz.de/en/" target="_blank">German International Cooperation (GIZ)</a>, and <a href="http://www.worldbank.org/" target="_blank">World Bank</a>. </blockquote> <p> This year theme is "Next Generation Solutions for Clean Air and Sustainable Transport − Towards a Livable Society in Asia": </p> <blockquote style='color:#444'> <p> Recognizing that clean air and sustainable transport are essential to a livable society in Asia, we call for innovative and <b>smart solutions (policy, institution, technology and financing)</b> that significantly reduce air pollution and greenhouse gases from energy, industry, transport, and area sources, and ensure a safe, equitable, environment and people-friendly transport system by accelerating the shift towards more environmentally sustainable transport (EST) in Asian cities and countries. </p> </blockquote> <p> Check out the <a href='http://www.baq2014est.org/program.html' target="_blank">program</a>. More than 800 participants are expected to join the BAQ 2014, and we will be part of them, presenting our recent research on <a href='/images/baq2014/aqicn-affordable_aqi_sensors-baq2014.pdf'> affordable air quality monitoring solution</a> we have been conducting within our <a href='/research'>research lab</a>. </p> <div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2014-09-06/australian-air-quality-comparison-with-the-us-epa-aqi-scale/' class='faqlisttitle'>Australian Air Quality: Comparison with the US EPA AQI scale.</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>September 6<sup>th</sup> 2014</small><div><small>https://aqicn.org/faq/2014-09-06/australian-air-quality-comparison-with-the-us-epa-aqi-scale/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2014-09-06/australian-air-quality-comparison-with-the-us-epa-aqi-scale/"'> <style> table.fancy { border: 2px solid black; border-spacing: 0px; background: white; } table.fancy td { margin: 0px; padding: 3px; text-align: center; border-bottom: solid 1px #DEDEDE; border-right: solid 1px #DEDEDE; font-size: 13px; } table.fancy tr:hover { background: #9AC9FF; } </style> <div style='float:right;padding-left:20px;text-align:center;'> <img src='/air/view/experiments/images/aqi.png' width=200> </div> <p> The Air Quality data for <a href='/city/perth/'>Perth</a> and <a href='/map/westernaustralia/'>Western Australia</a> is finally available after a long waiting time. </p> <p> The department of Environmental Regulation (D.E.R.) from the government of Western Australia, is now publishing the data on their site: <a href='http://www.der.wa.gov.au/your-environment/air'>der.wa.gov.au/your-environment/air</a>. </p> <p> While the link to the <a href='http://www.dec.wa.gov.au/pollution-prevention/air-quality/air-quality-data.html'>DEC site</a> is still not working, the feed can be accessed from this new <a href='http://www.der.wa.gov.au/component/newsfeeds/newsfeed/53-air-quality/1-air-quality-data?Itemid=101'> page</a>. </p> <br><br> <center><a href='https://aqicn.org/faq/2014-09-06/australian-air-quality-comparison-with-the-us-epa-aqi-scale/' class='faq-read-more'>Read the full article</a></center><br><br><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2014-08-01/haier-air-box-can-it-provide-any-useful-air-quality-information/' class='faqlisttitle'>Haier air box: Can it provide any useful Air Quality information?</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>August 1<sup>st</sup> 2014</small><div><small>https://aqicn.org/faq/2014-08-01/haier-air-box-can-it-provide-any-useful-air-quality-information/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2014-08-01/haier-air-box-can-it-provide-any-useful-air-quality-information/"'><style type="text/css"> </style> <div style='float:right;padding-left:10px;'> <a href='http://item.jd.com/1159948.html' target=_jd> <img src='/images/haierairbox/airbox-green.jpg' border=0 height=300> </a> <br> </a> </div> <p> You might have stumbled on one of Haier recent product called the "Air Box" (海尔空气盒子), available from <a href='http://item.jd.com/1159948.html' target=_jd>jd.com</a> or <a href='http://s.taobao.com/search?q=%BA%A3%B6%FB%BF%D5%C6%F8%BA%D0%D7%D3&s_from=newHeader&ssid=s5-e&search_type=item&sourceId=tb.item' target=_taobao >taobao</a> for an affordable 399RMB. It is very <a href='http://www.red-dot-21.com/products/haier-air-box-air-purifier-22140' target=_ style='color:black;'>beautifully designed</a> product, aimed, as part of their <a style='color:black;' href='http://technode.com/2014/03/19/chinese-home-appliance-makers-internet-companies-rush-to-smart-home-market/' target=_>smart living</a> concept, at being used in conjunction with smart air conditioner. </p> <p> It <i>*claims*</i> to be able to detect and measure both <a style='color:black;' href='http://en.wikipedia.org/wiki/Volatile_organic_compound' target=_>Volatile Organic Compound</a> (VOC, i.e Ozone), as well as the famous small PM2.5 particulate matter. But can it really do so? To know the answer, check our latest on-going experiment about the Air Box at <a href='/experiments/haier-air-box/'>experiments/haier-air-box</a> </p> <br> <br> <center> <img src='/images/haierairbox/airbox-scale.jpg' border=0 style='max-width:100%'> </center> <center><br>-<svg xmlns="http://www.w3.org/2000/svg" width="28" height="28" version="1" viewBox="0 0 26 26" enable-background="new 0 0 26 26"><path d="M 15.65625 -0.03125 C 14.280846 -0.03760636 12.828752 0.09254274 11.3125 0.40625 C 8.28651 1.0323169 5.7746616 2.1709106 3.96875 3.59375 C 2.3885774 4.8387345 1.3097647 6.3321654 1.0625 7.96875 A 1.0001 1.0001 0 0 0 1 8.40625 C 1 8.4709766 0.99753847 8.5296394 1 8.59375 C 0.99939321 8.6245955 1 8.6565744 1 8.6875 C 1.0067678 8.8049913 1.0164368 8.9159604 1.03125 9.03125 C 1.0536237 9.2185949 1.1014372 9.4156735 1.15625 9.59375 C 1.4590854 10.826485 2.2046296 11.91918 3.21875 12.78125 C 4.0779092 13.511593 5.1369309 14.083861 6.3125 14.53125 A 1.0001 1.0001 0 0 0 6.53125 14.9375 C 8.1339345 16.910035 12.101162 19.118434 18.1875 18.59375 A 1.0043849 1.0043849 0 0 0 18 16.59375 C 14.906411 16.860439 12.500325 16.269357 10.78125 15.5 C 14.30154 15.772761 18.245209 15.070028 21.71875 12.96875 A 1.0021949 1.0021949 0 1 0 20.6875 11.25 C 16.887924 13.548509 12.317006 14.000584 8.78125 13.21875 C 8.6725971 13.194724 8.5753958 13.151278 8.46875 13.125 C 10.108287 13.189898 11.88322 13.060799 13.6875 12.6875 C 16.718701 12.060355 19.36029 10.886006 21.21875 9.4375 C 23.067114 7.9968631 24.272087 6.1533076 23.875 4.21875 C 23.8732 4.20861 23.8769 4.197602 23.875 4.1875 C 23.513143 2.2541955 21.685558 1.0369822 19.4375 0.4375 C 18.307598 0.13619269 17.031654 -0.02489364 15.65625 -0.03125 z M 15.65625 1.96875 C 16.883971 1.97489 18.004902 2.1263073 18.9375 2.375 C 20.802695 2.8723854 21.754612 3.7133252 21.90625 4.5625 A 1.0001 1.0001 0 0 0 21.9375 4.625 C 22.12047 5.4788616 21.54154 6.6735055 20 7.875 C 18.45846 9.0764945 16.081299 10.145895 13.3125 10.71875 C 10.546306 11.291066 7.7660826 11.269646 5.8125 10.78125 C 4.8357087 10.537052 4.0847823 10.157122 3.625 9.78125 C 3.3682882 9.5713881 3.1893221 9.3858538 3.09375 9.1875 C 3.0413411 8.9743851 3.0082478 8.7545393 3 8.53125 C 3.0633474 7.4789308 3.7648202 6.2771492 5.1875 5.15625 C 6.6815884 3.9790894 8.91349 2.9489331 11.6875 2.375 C 13.071248 2.0887073 14.428529 1.9626064 15.65625 1.96875 z M 15.96875 3.65625 C 14.93792 3.617106 13.843984 3.69192 12.71875 3.90625 A 1.0001 1.0001 0 0 0 12.6875 3.9375 C 9.8940815 4.582135 7.6159262 5.8506824 6.5625 7.5625 A 1.0001 1.0001 0 1 0 8.25 8.625 C 8.7942179 7.740646 10.701734 6.434394 13.09375 5.875 C 13.10453 5.87295 13.11421 5.87702 13.125 5.875 C 15.064267 5.5112859 17.031887 5.6468794 18.03125 6.03125 A 1.0040202 1.0040202 0 0 0 18.75 4.15625 C 17.952461 3.8495042 16.99958 3.6953943 15.96875 3.65625 z M 9.15625 17.59375 A 1.0001 1.0001 0 0 0 8.5625 19.25 C 8.5625 19.25 11.033033 22.015963 15.53125 21.90625 A 1.0004882 1.0004882 0 1 0 15.46875 19.90625 C 11.766967 19.996537 10.0625 17.9375 10.0625 17.9375 A 1.0001 1.0001 0 0 0 9.15625 17.59375 z M 8.125 20.1875 A 1.0001 1.0001 0 0 0 7.40625 21.65625 C 7.40625 21.65625 8.6869767 23.974979 11.65625 24.09375 A 1.001098 1.001098 0 0 0 11.75 22.09375 C 9.7192733 22.012521 9.1875 20.75 9.1875 20.75 A 1.0001 1.0001 0 0 0 8.21875 20.1875 A 1.0001 1.0001 0 0 0 8.125 20.1875 z M 7.59375 23.0625 A 1.0001 1.0001 0 0 0 7.4375 23.09375 A 1.0001 1.0001 0 0 0 6.9375 23.34375 C 6.9375 23.34375 6.19375 24 5.09375 24 A 1.0001 1.0001 0 1 0 5.09375 26 C 6.99375 26 8.28125 24.84375 8.28125 24.84375 A 1.0001 1.0001 0 0 0 7.59375 23.0625 z" color="#000" ></path></svg>-<br><br></center> <div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2014-07-21/windows-mobile-application-now-available-from-the-microsoft-app-store/' class='faqlisttitle'>Windows Mobile Application now available from the Microsoft App-Store</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>July 21<sup>st</sup> 2014</small><div><small>https://aqicn.org/faq/2014-07-21/windows-mobile-application-now-available-from-the-microsoft-app-store/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2014-07-21/windows-mobile-application-now-available-from-the-microsoft-app-store/"'><style type="text/css"> img.winmothumbnail { width:150px; height:250px; } .winmothumbnailcrop { height: 250px; overflow: hidden; display: inline-block; border:1px solid #eee; margin:5px; -box-shadow: 0 1px 3px rgba(0,0,0,0.5); -moz-box-shadow: 0 1px 3px rgba(0,0,0,0.5); -webkit-box-shadow: 0 1px 3px rgba(0,0,0,0.5); } </style> <div style='float:right;padding-left:10px;'> <img src='/images/winmo/lumia.jpg' border=0 height=350> </a> </div> The Windows Mobile 8 phone application is now available for download from the Microsoft Application Store: <a href='' target=_></a> <br> <br> <center> <a href='' target=_> <div class="winmothumbnailcrop"><img src='/images/winmo/winmo.4.jpg' class='winmothumbnail'></div> <div class="winmothumbnailcrop"><img src='/images/winmo/winmo.1.jpg' class='winmothumbnail'></div> <div class="winmothumbnailcrop"><img src='/images/winmo/winmo.3.jpg' class='winmothumbnail'></div> <div class="winmothumbnailcrop"><img src='/images/winmo/winmo.2.jpg' class='winmothumbnail'></div> <div class="winmothumbnailcrop"><img src='/images/winmo/winmo.5.jpg' class='winmothumbnail'></div> </a> </center> <br> <center><a href='https://aqicn.org/faq/2014-07-21/windows-mobile-application-now-available-from-the-microsoft-app-store/' class='faq-read-more'>Read the full article</a></center><br><br> <div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2013-10-21/dylos-air-particule-conter-experiment-maintenance/' class='faqlisttitle'>Dylos Air Particule Conter experiment maintenance.</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>October 21<sup>st</sup> 2013</small><div><small>https://aqicn.org/faq/2013-10-21/dylos-air-particule-conter-experiment-maintenance/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-10-21/dylos-air-particule-conter-experiment-maintenance/"'> <br> <br> <div style='border:1px solid #ccc;background: #f8f8f8;margin:10px 0;padding: 10px;font-size: 100%;'> <a href='/products/gaia'> <img src='/air/view/products/images/gaia-a12-mounting-with-strips-01.jpg' style='float:right;width:100px;'> </a> <p> Note: this article was written in 2013. While the Dylos monitor is still a good product, there is nowdays much better and affordable monitoring products, so we do not recommend purchasing the Dylos product anymore. </p> <center> <div style='height:1px;width: 33%;border-top:1px solid #888;margin:5px;'></div> </center> <p> You can for instance check the <a href='/products/gaia/'>GAIA air quality monitoring stations</a> product range from ES Labs. </p> <div style='clear:both'></div> </div> <br> <br> <p> The <a href='/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1/'>Dylos Air Particle Counter experiment</a> is still going-on, and has been on for now 50 days. So, last weekend, as the air pollution in Beijing was getting really low - thanks to strong north winds, we used this time as an opportunity to perform a maintenance break... on the Dylos monitor itself. </p> <p> The reason is that, even if the Dylos monitor is definitely well designed and engineered equipment (we do mean it), it maybe not be so well conceived to subsist Beijing's tough episodic Air Pollution. </p> <p> It all started after noticing that the correlation graphs between the Dylos and BAM monitor tend to show some systematic signs of leveling beyond 38,000 particles (≥0.5µ). This kind of saturation symptom can be the consequence of internal air inflow bottleneck, which can be caused by "saturated" air channels. During times of heavy pollution, this phenomenon is totally normal due to the large amount of particulate matter having to go through the air channel. </p> <p> So, no surprise, after opening the Dylos monitor, we confirmed that the internal air channels are definitely saturated, by an accumulation of dust during the last 50 days: </p> <center> <img src='/images/dusty-dylos-monitor-1.jpg' height=350 border=0 style='max-width:100%' title='Dust accumulated in the Dylos air particles counter front sensor area (laser and photodiode sensor)'>   <img src='/images/dusty-dylos-monitor-2.jpg' height=350 border=0 style='max-width:100%' title='Dust accumulated in the Dylos air particle counter back air channel area'> <br> -<i>Beijing dust impact on the Dylos air particle counter internal structure</i>- </center> <p> The result of cleaning the internal structure, using a fine brush, would produce an astonishing amount of dust - and this, just after 50 days of outdoor experimentation. Just think that this is what you are breathing... </p> <center> <img src='/images/beijing-dust-1.jpg' width=80% max-width=930px border=0 style='max-width:100%' title='close look up at Beijing dust accumulated though the Dylos air particle monitor'> <br>-<i>The real Beijing dust... the one Beijiners breathe during heavy pollution day!</i>- </center> <p> Actually, having to perform such cleaning and maintenance on the Dylos equipment is not a surprise, since even the very expensive BAM equipment requires monthly maintenance by skilled operators. </p> <center><br>-<svg xmlns="http://www.w3.org/2000/svg" width="28" height="28" version="1" viewBox="0 0 26 26" enable-background="new 0 0 26 26"><path d="M 15.65625 -0.03125 C 14.280846 -0.03760636 12.828752 0.09254274 11.3125 0.40625 C 8.28651 1.0323169 5.7746616 2.1709106 3.96875 3.59375 C 2.3885774 4.8387345 1.3097647 6.3321654 1.0625 7.96875 A 1.0001 1.0001 0 0 0 1 8.40625 C 1 8.4709766 0.99753847 8.5296394 1 8.59375 C 0.99939321 8.6245955 1 8.6565744 1 8.6875 C 1.0067678 8.8049913 1.0164368 8.9159604 1.03125 9.03125 C 1.0536237 9.2185949 1.1014372 9.4156735 1.15625 9.59375 C 1.4590854 10.826485 2.2046296 11.91918 3.21875 12.78125 C 4.0779092 13.511593 5.1369309 14.083861 6.3125 14.53125 A 1.0001 1.0001 0 0 0 6.53125 14.9375 C 8.1339345 16.910035 12.101162 19.118434 18.1875 18.59375 A 1.0043849 1.0043849 0 0 0 18 16.59375 C 14.906411 16.860439 12.500325 16.269357 10.78125 15.5 C 14.30154 15.772761 18.245209 15.070028 21.71875 12.96875 A 1.0021949 1.0021949 0 1 0 20.6875 11.25 C 16.887924 13.548509 12.317006 14.000584 8.78125 13.21875 C 8.6725971 13.194724 8.5753958 13.151278 8.46875 13.125 C 10.108287 13.189898 11.88322 13.060799 13.6875 12.6875 C 16.718701 12.060355 19.36029 10.886006 21.21875 9.4375 C 23.067114 7.9968631 24.272087 6.1533076 23.875 4.21875 C 23.8732 4.20861 23.8769 4.197602 23.875 4.1875 C 23.513143 2.2541955 21.685558 1.0369822 19.4375 0.4375 C 18.307598 0.13619269 17.031654 -0.02489364 15.65625 -0.03125 z M 15.65625 1.96875 C 16.883971 1.97489 18.004902 2.1263073 18.9375 2.375 C 20.802695 2.8723854 21.754612 3.7133252 21.90625 4.5625 A 1.0001 1.0001 0 0 0 21.9375 4.625 C 22.12047 5.4788616 21.54154 6.6735055 20 7.875 C 18.45846 9.0764945 16.081299 10.145895 13.3125 10.71875 C 10.546306 11.291066 7.7660826 11.269646 5.8125 10.78125 C 4.8357087 10.537052 4.0847823 10.157122 3.625 9.78125 C 3.3682882 9.5713881 3.1893221 9.3858538 3.09375 9.1875 C 3.0413411 8.9743851 3.0082478 8.7545393 3 8.53125 C 3.0633474 7.4789308 3.7648202 6.2771492 5.1875 5.15625 C 6.6815884 3.9790894 8.91349 2.9489331 11.6875 2.375 C 13.071248 2.0887073 14.428529 1.9626064 15.65625 1.96875 z M 15.96875 3.65625 C 14.93792 3.617106 13.843984 3.69192 12.71875 3.90625 A 1.0001 1.0001 0 0 0 12.6875 3.9375 C 9.8940815 4.582135 7.6159262 5.8506824 6.5625 7.5625 A 1.0001 1.0001 0 1 0 8.25 8.625 C 8.7942179 7.740646 10.701734 6.434394 13.09375 5.875 C 13.10453 5.87295 13.11421 5.87702 13.125 5.875 C 15.064267 5.5112859 17.031887 5.6468794 18.03125 6.03125 A 1.0040202 1.0040202 0 0 0 18.75 4.15625 C 17.952461 3.8495042 16.99958 3.6953943 15.96875 3.65625 z M 9.15625 17.59375 A 1.0001 1.0001 0 0 0 8.5625 19.25 C 8.5625 19.25 11.033033 22.015963 15.53125 21.90625 A 1.0004882 1.0004882 0 1 0 15.46875 19.90625 C 11.766967 19.996537 10.0625 17.9375 10.0625 17.9375 A 1.0001 1.0001 0 0 0 9.15625 17.59375 z M 8.125 20.1875 A 1.0001 1.0001 0 0 0 7.40625 21.65625 C 7.40625 21.65625 8.6869767 23.974979 11.65625 24.09375 A 1.001098 1.001098 0 0 0 11.75 22.09375 C 9.7192733 22.012521 9.1875 20.75 9.1875 20.75 A 1.0001 1.0001 0 0 0 8.21875 20.1875 A 1.0001 1.0001 0 0 0 8.125 20.1875 z M 7.59375 23.0625 A 1.0001 1.0001 0 0 0 7.4375 23.09375 A 1.0001 1.0001 0 0 0 6.9375 23.34375 C 6.9375 23.34375 6.19375 24 5.09375 24 A 1.0001 1.0001 0 1 0 5.09375 26 C 6.99375 26 8.28125 24.84375 8.28125 24.84375 A 1.0001 1.0001 0 0 0 7.59375 23.0625 z" color="#000" ></path></svg>-<br><br></center> <p>The following part has been added 10 days after the initial post was published:</p> <p> It is now 10 days since the cleaning has been done, and the situation has definitely improved for the correlation between BAM and Dylos. From the graph below, which shows the measurements before and after the cleaning, the zone indicated with number <b>(2)</b> shows a very good similarity (correlation) between BAM and Dylos. But, under condition of heavy pollution, there are still consistent signs of leveling (deviation in measurement), as highlighted with zone number <b>(1)</b> and <b>(3)</b>. The deviation seems however less worse after the cleaning (zone <b>(3)</b>) than before (zone <b>(1)</b>). We are contacting the Dylos company, to consult them on this leveling phenomenon, and will update this post later. </p> <br> <br> <center> <a href='/sensor/beijing/sanlitun/'> <img src='/images/dylos-monitor-vs-bam-monitor-correlation-impact-after-cleaning-1.jpg' width=80% max-width=930px border=0 style='max-width:100%'> </a> <br> <i>(Click on the picture to open the real time version)</i> <br> </center> <center><br>-<svg xmlns="http://www.w3.org/2000/svg" width="28" height="28" version="1" viewBox="0 0 26 26" enable-background="new 0 0 26 26"><path d="M 15.65625 -0.03125 C 14.280846 -0.03760636 12.828752 0.09254274 11.3125 0.40625 C 8.28651 1.0323169 5.7746616 2.1709106 3.96875 3.59375 C 2.3885774 4.8387345 1.3097647 6.3321654 1.0625 7.96875 A 1.0001 1.0001 0 0 0 1 8.40625 C 1 8.4709766 0.99753847 8.5296394 1 8.59375 C 0.99939321 8.6245955 1 8.6565744 1 8.6875 C 1.0067678 8.8049913 1.0164368 8.9159604 1.03125 9.03125 C 1.0536237 9.2185949 1.1014372 9.4156735 1.15625 9.59375 C 1.4590854 10.826485 2.2046296 11.91918 3.21875 12.78125 C 4.0779092 13.511593 5.1369309 14.083861 6.3125 14.53125 A 1.0001 1.0001 0 0 0 6.53125 14.9375 C 8.1339345 16.910035 12.101162 19.118434 18.1875 18.59375 A 1.0043849 1.0043849 0 0 0 18 16.59375 C 14.906411 16.860439 12.500325 16.269357 10.78125 15.5 C 14.30154 15.772761 18.245209 15.070028 21.71875 12.96875 A 1.0021949 1.0021949 0 1 0 20.6875 11.25 C 16.887924 13.548509 12.317006 14.000584 8.78125 13.21875 C 8.6725971 13.194724 8.5753958 13.151278 8.46875 13.125 C 10.108287 13.189898 11.88322 13.060799 13.6875 12.6875 C 16.718701 12.060355 19.36029 10.886006 21.21875 9.4375 C 23.067114 7.9968631 24.272087 6.1533076 23.875 4.21875 C 23.8732 4.20861 23.8769 4.197602 23.875 4.1875 C 23.513143 2.2541955 21.685558 1.0369822 19.4375 0.4375 C 18.307598 0.13619269 17.031654 -0.02489364 15.65625 -0.03125 z M 15.65625 1.96875 C 16.883971 1.97489 18.004902 2.1263073 18.9375 2.375 C 20.802695 2.8723854 21.754612 3.7133252 21.90625 4.5625 A 1.0001 1.0001 0 0 0 21.9375 4.625 C 22.12047 5.4788616 21.54154 6.6735055 20 7.875 C 18.45846 9.0764945 16.081299 10.145895 13.3125 10.71875 C 10.546306 11.291066 7.7660826 11.269646 5.8125 10.78125 C 4.8357087 10.537052 4.0847823 10.157122 3.625 9.78125 C 3.3682882 9.5713881 3.1893221 9.3858538 3.09375 9.1875 C 3.0413411 8.9743851 3.0082478 8.7545393 3 8.53125 C 3.0633474 7.4789308 3.7648202 6.2771492 5.1875 5.15625 C 6.6815884 3.9790894 8.91349 2.9489331 11.6875 2.375 C 13.071248 2.0887073 14.428529 1.9626064 15.65625 1.96875 z M 15.96875 3.65625 C 14.93792 3.617106 13.843984 3.69192 12.71875 3.90625 A 1.0001 1.0001 0 0 0 12.6875 3.9375 C 9.8940815 4.582135 7.6159262 5.8506824 6.5625 7.5625 A 1.0001 1.0001 0 1 0 8.25 8.625 C 8.7942179 7.740646 10.701734 6.434394 13.09375 5.875 C 13.10453 5.87295 13.11421 5.87702 13.125 5.875 C 15.064267 5.5112859 17.031887 5.6468794 18.03125 6.03125 A 1.0040202 1.0040202 0 0 0 18.75 4.15625 C 17.952461 3.8495042 16.99958 3.6953943 15.96875 3.65625 z M 9.15625 17.59375 A 1.0001 1.0001 0 0 0 8.5625 19.25 C 8.5625 19.25 11.033033 22.015963 15.53125 21.90625 A 1.0004882 1.0004882 0 1 0 15.46875 19.90625 C 11.766967 19.996537 10.0625 17.9375 10.0625 17.9375 A 1.0001 1.0001 0 0 0 9.15625 17.59375 z M 8.125 20.1875 A 1.0001 1.0001 0 0 0 7.40625 21.65625 C 7.40625 21.65625 8.6869767 23.974979 11.65625 24.09375 A 1.001098 1.001098 0 0 0 11.75 22.09375 C 9.7192733 22.012521 9.1875 20.75 9.1875 20.75 A 1.0001 1.0001 0 0 0 8.21875 20.1875 A 1.0001 1.0001 0 0 0 8.125 20.1875 z M 7.59375 23.0625 A 1.0001 1.0001 0 0 0 7.4375 23.09375 A 1.0001 1.0001 0 0 0 6.9375 23.34375 C 6.9375 23.34375 6.19375 24 5.09375 24 A 1.0001 1.0001 0 1 0 5.09375 26 C 6.99375 26 8.28125 24.84375 8.28125 24.84375 A 1.0001 1.0001 0 0 0 7.59375 23.0625 z" color="#000" ></path></svg>-<br><br></center><div style='display:inline-block;width:50%;border-top:1px solid black;margin-bottom:20px;'></article><article><div><a href='https://aqicn.org/faq/2013-09-09/revised-pm25-aqi-breakpoints/' class='faqlisttitle'>Revised PM<sub>2.5</sub> AQI breakpoints</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>September 9<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-09-09/revised-pm25-aqi-breakpoints/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-09-09/revised-pm25-aqi-breakpoints/"'> <p> For some historical reason, the AQI convertion formula used for some of the cities on the World Air Quality Index project were not using the <a href='http://www.epa.gov/airquality/particlepollution/2012/decfsstandards.pdf' target=_> updated 2012 EPA PM<sub>2.5</sub> standard</a>. (This is only relevant for cities in Asia, like Japan and Taiwan. Other continents (America, Europe and Australia) have always been using the 2012 standard. </p> <p> The main change is this updated EPA standard, published on December 14th 2012, compared to the previous one (published in 1999), is to reduce (limit) the PM<sub>2.5</sub> AQI level 50 from 15µg/m<sup>3</sup> to 12µg/m<sup>3</sup>, and this in order to enforce more strict air quality standards. </p> <p> Since September 9th 2013, all the countries are now using the same PM2.5 AQI conversion scale, which is reflected in this table: </p> <br> <br><center><a href='https://aqicn.org/faq/2013-09-09/revised-pm25-aqi-breakpoints/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1/' class='faqlisttitle'>Dylos Air Particule counter experimentation, part 1.</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>September 8<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1/"'> <div style='float:right;padding-left:10px;'> <img src='/air/faq/images/FPM-377.png' border=0> </div> <p> The most common way to measure air quality, as far as it concerns PM<sub>10</sub> and PM<sub>2.5</sub> particules, is to use the so-called <i>Beta Attenuation Monitors</i>, aka BAM (see picture on the right). Those are profesional equipment, and also the only official equipment used for Air Quality monitoring in China, US, and most of the world. The most famous manufacter is the US-based company called <a href='http://www.metone.com/' target=_>Met-One</a>. </p> <p> The BAM working principle is quite simple: It measures the decrease in the number of beta particles (electrons) transmitted through a thin layer of particulate matter (PM). As the thickness of the PM layer is increased, the lower the number of beta particules can go through. </p> <br> <br> <center> <a href='http://alg.umbc.edu/umap/bam_index.html' target=_> <img src='/air/faq/images/bam.jpg' width=500 style='max-width:100%' border=0> </a> </center> <br> <br> <p> The only problem with this kind of BAM equipment is that the cost, estimated to 120K CNY (15K EUR). In China only, there are around 500 of those (around 10 station for each city), and yet, this is not enough as there are still many cities without any PM<sub>2.5</sub> readings. In Thailand, there are 21 automatic (i.e. with hourly reading) stations, but none of them provide PM<sub>2.5</sub> data. And in Vietnam, there are only 3 stations for the entire country. </p> <br><center><a href='https://aqicn.org/faq/2013-09-08/dylos-air-particule-counter-experimentation-part-1/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-06-25/singapore-psi-and-pm25-aqi-why-is-there-a-difference-between-the-two-readings/' class='faqlisttitle'>Singapore PSI and PM<sub>2.5</sub> AQI: Why is there a difference between the two readings?</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>June 25<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-06-25/singapore-psi-and-pm25-aqi-why-is-there-a-difference-between-the-two-readings/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-06-25/singapore-psi-and-pm25-aqi-why-is-there-a-difference-between-the-two-readings/"'> <p> With the recent <a href='http://www.reuters.com/article/2013/06/25/southeastasia-haze-idUSL3N0F043720130625'>Southeast Asia Smog from Indonesia</a> affecting Singapore and now <a href='http://www.bbc.co.uk/news/world-asia-23018947' target=_>Malaysia</a>, we got many questions about why there is a difference between the data which can be read from Singapore NEA website (<a href='http://nea.gov.sg/' target=_>nea.gov.sg</a>) and the World Air Quality Index project <a href='/city/singapore/central/'>Singapore webpage</a>. </p> <p> For instance, here is what can be read today in NEA website: </p> <center> <img src='/images/nea.sg.png' width=600 style='max-width:100%'> </center> <br> <br><center><a href='https://aqicn.org/faq/2013-06-25/singapore-psi-and-pm25-aqi-why-is-there-a-difference-between-the-two-readings/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-05-20/shenyang-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shenyang/' class='faqlisttitle'>Shenyang PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 3 measurement stations in Shenyang</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>May 20<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-05-20/shenyang-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shenyang/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-05-20/shenyang-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shenyang/"'> Shenyang city AQI data is now based on the maximum of the <a href='https://aqicn.org/city/shenyang/usconsulate/'>Shenyang US Consulate (沈阳美国总领事馆)</a>, <a href='https://aqicn.org/city/china/shenyang/taiyuanjie/'>Taiyuan Street, Shenyang (沈阳太原街)</a> and <a href='https://aqicn.org/city/china/shenyang/beiling/'>Beiling, Shenyang (沈阳北陵)</a>. For more infomation, please refer to the article about <a href='/faq/2013-01-19/shanghai-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shanghai'> Shanghai AQI. <br><br> <br><center><a href='https://aqicn.org/faq/2013-05-20/shenyang-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shenyang/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-02-07/air-quality-designation-update-to-the-epa-airnow-standard/' class='faqlisttitle'>Air Quality Designation: Update to the EPA AirNow standard</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>February 7<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-02-07/air-quality-designation-update-to-the-epa-airnow-standard/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-02-07/air-quality-designation-update-to-the-epa-airnow-standard/"'> <p> For historic reason, the World Air Quality Index project has been using the China MEP (Ministry of Environmental Protection) designation for the air quality levels. This is now past history, and the designation will follow, from now on, the US EPA (Environmental Protection Agency) <a href='http://www.airnow.gov/index.cfm?action=aqibasics.aqi'> AirNow standards</a>. </p> <p> The table below summarizes the differences in designation between the two standards, as well as the translations for the various languages. </p> <br><center><a href='https://aqicn.org/faq/2013-02-07/air-quality-designation-update-to-the-epa-airnow-standard/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-02-03/can-masks-really-filter-the-particulate-matter-as-small-as-pm25/' class='faqlisttitle'>Can masks really filter the particulate matter as small as PM<sub>2.5</sub>?</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>February 3<sup>rd</sup> 2013</small><div><small>https://aqicn.org/faq/2013-02-03/can-masks-really-filter-the-particulate-matter-as-small-as-pm25/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-02-03/can-masks-really-filter-the-particulate-matter-as-small-as-pm25/"'> <div style='float:right;'> <a href='https://www.e-junkie.com/ecom/gb.php?cl=103349&c=ib&aff=217216' target='toto3'> <img src='/images/totobobo/icon-ttle.jpg' border=0> </a> </div> <p> While discussing today about the faq entry on <a href='/faq/2013-02-02/why-is-pm25-often-higher-than-pm10'> PM<sub>10</sub> versus PM<sub>2.5</sub></a> which I posted yesterday, my friend Klaus challenged on the usefulness of protection masks. He was actually wondering if the modern masks can nowadays really filter efficiently all the small harmful PM<sub>2.5</sub> particulate matter? </p> <p> Actually, this is a very good question! If you have to wear a mask in Beijing, then better to make sure that it really filters the bad particulates. </p> <p> Since I did not have the answer to his question, I just dropped an email to Francis Chu from the Singapore <a href='https://www.e-junkie.com/ecom/gb.php?cl=103349&c=ib&aff=217216' target='toto1'>totobobo</a><sup>®</sup> mask manufacturing company, who replied in almost no time: </p> <br><center><a href='https://aqicn.org/faq/2013-02-03/can-masks-really-filter-the-particulate-matter-as-small-as-pm25/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-02-02/why-is-pm25-often-higher-than-pm10/' class='faqlisttitle'>Why is PM2.5 often higher than PM10? Is PM10 still a relevant measure?</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>February 2<sup>nd</sup> 2013</small><div><small>https://aqicn.org/faq/2013-02-02/why-is-pm25-often-higher-than-pm10/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-02-02/why-is-pm25-often-higher-than-pm10/"'> <p> We got a very good and relevant question this week from Severine P., who asked about pm2.5 concentrations versus pm10 concentrations. What Severine asked in her mail was: </p> <blockquote> <p> I don't understand why pm2.5 concentrations are often higher than pm10 concentrations.<br> Aren't PM smaller than 2.5 micro included in PM smaller than 10 micro?<br> Thank you for your answer</p> </blockquote> <p> Severine's question is totally correct: PM2.5 are, by definition, particulates smaller than 2.5 micrometers, so indeed, they should also be included as smaller than 10 micrometers. </p> <br><center><a href='https://aqicn.org/faq/2013-02-02/why-is-pm25-often-higher-than-pm10/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-01-19/shanghai-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shanghai/' class='faqlisttitle'>Shanghai PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 3 measurement stations in Shanghai</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>January 19<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-01-19/shanghai-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shanghai/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-01-19/shanghai-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shanghai/"'> Shanghai AQI data is now based on the maximum PM<sub>2.5</sub> AQI data for 3 stations: <a href='https://aqicn.org/city/shanghai/us-consulate/'>Shanghai US Consulate (上海美国总领事馆)</a>, <a href='https://aqicn.org/city/shanghai/jinganjiancezhan/'>Jing'an Monitoring Station (静安监测站)</a> <br> and <a href='https://aqicn.org/city/shanghai/luwanshizhuanfuxiao/'>lúwān shī zhuān fùxiǎo (上海师范专科学校附属小学)</a>. <br><br> The first station is maintained by <a href='http://shanghai.usembassy-china.org.cn/airmonitor.html' target=_>US Consulate in Shanghai</a>, while the two last ones are provided by <a href='http://www.semc.gov.cn/' target=_>Shanghai Environment Monitoring Center(上海市环境监测中心)</a>, which is governmental center. <br><br> If you have concerns about some stations reporting lower PM<sub>2.5</sub> data compared to others, then refer to the following graphics; they show the relative PM<sub>2.5</sub> reporting for the last 5 days for each of the above mentioned stations: <br><br> <br><center><a href='https://aqicn.org/faq/2013-01-19/shanghai-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-shanghai/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-01-11/chengdu-pm25-main-aqi-update-comparative-pm25-data-for-2-measurement-stations-in-chengdu/' class='faqlisttitle'>Chengdu PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 2 measurement stations in Chengdu</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>January 11<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-01-11/chengdu-pm25-main-aqi-update-comparative-pm25-data-for-2-measurement-stations-in-chengdu/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-01-11/chengdu-pm25-main-aqi-update-comparative-pm25-data-for-2-measurement-stations-in-chengdu/"'> For more information, please refer to the Shanghai AQI update explanations. The following graphics show the relative PM<sub>2.5</sub> AQI data for Chengdu stations on which the overall Chengu AQI is based. <br><br> <br><center><a href='https://aqicn.org/faq/2013-01-11/chengdu-pm25-main-aqi-update-comparative-pm25-data-for-2-measurement-stations-in-chengdu/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><article><div><a href='https://aqicn.org/faq/2013-01-11/beijing-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-beijing/' class='faqlisttitle'>Beijing PM<sub>2.5</sub> main AQI update: Comparative PM<sub>2.5</sub> data for 3 measurement stations in Beijing</a></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><small style='color:#888;'>January 11<sup>th</sup> 2013</small><div><small>https://aqicn.org/faq/2013-01-11/beijing-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-beijing/</small></div><div style='height:1px;background-color:#aaaaaa;width:80px;margin-top:5px;'></div><div class='entry-content;' style='min-height:250px;cursor:pointer;' onclick='window.location="https://aqicn.org/faq/2013-01-11/beijing-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-beijing/"'> For more information, please refer to the Shanghai AQI update explanations. The following graphics show the relative PM<sub>2.5</sub> AQI data for Beijing stations on which the overall Beijing AQI is based. <br><br> <br><center><a href='https://aqicn.org/faq/2013-01-11/beijing-pm25-main-aqi-update-comparative-pm25-data-for-3-measurement-stations-in-beijing/' class='faq-read-more'><i18n>Read the full article</i18n></a></center><br><br></article><br><br><br></div></div></div><a name="infoaqi"></a><div class='h1section h1section-divider'><div class='h1section-rainbow'><div></div><div></div><div></div><div></div><div></div></div><h1><div id='h1header2' style='padding:2px;font-family:"Noto Serif",Cambria,"Palatino Linotype","Book Antiqua","URW Palladio L",serif;;' i18n>About the Air Quality and Pollution Measurement:</div></h1></div><script type='text/javascript'> ; if (!isMobileUA) { fitLine('#h1header2',.88,{maxfs:45}); }; </script><div class='whitebody' style='font-family:"Noto Serif",Cambria,"Palatino Linotype","Book Antiqua","URW Palladio L",serif;'><div class='section-outer'><div class='section-content' ><center>About the Air Quality Levels<br><br><style type="text/css">#legend-full table.infoaqitable {line-height: 1.5;background-color: white;max-width: 1000px;width: 95%;margin: 0px;border: 1px solid black;cursor: pointer;}#legend-full table.infoaqitable td {padding: 5px;font-size: 15px;text-shadow: none;}#legend-full .aqiwtxt {color: #ffffff;}#legend-full .aqibtxt {color: #000000;}@media only screen and (max-width: 800px) {#legend-full table.infoaqitable {width: 98%;}}@media only screen and (max-width: 800px) {#legend-full table.infoaqitable td {display: block;}#legend-full table.infoaqitable td:nth-child(1) {display: inline-block;font-size: 1.2em;}#legend-full table.infoaqitable td:nth-child(2) {display: inline-block;font-weight: 800;font-size: 1.2em;}}</style><div id='legend-full' onclick='window.location="/scale/"'><table class="infoaqitable cautionary"><thead><tr><td>AQI</td><td i18n='generic'>Air Pollution Level</td><td i18n='generic'>Health Implications</td><td i18n='generic'>Cautionary Statement (for PM2.5)</td></tr></thead><tr style="background-color:#009966;"><td class='aqiwtxt' nowrap="true">0 - 50</td><td class='aqiwtxt' i18n='generic'>Good</td><td class='aqiwtxt' i18n='generic'>Air quality is considered satisfactory, and air pollution poses little or no risk</td><td class='aqiwtxt' i18n='generic'>None</td></tr><tr style="background-color:#ffde33" class='aqibtxt'><td class='aqibtxt' nowrap="true">51 -100</td><td class='aqibtxt' i18n='generic'>Moderate</td><td class='aqibtxt' i18n='generic'>Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.</td><td class='aqibtxt' i18n='generic'>Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.</td></tr><tr style="background-color:#ff9933;"><td class='aqibtxt' nowrap="true">101-150</td><td class='aqibtxt' i18n='generic'>Unhealthy for Sensitive Groups</td><td class='aqibtxt' i18n='generic'>Members of sensitive groups may experience health effects. The general public is not likely to be affected.</td><td class='aqibtxt' i18n='generic'>Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor exertion.</td></tr><tr style="background-color:#cc0033;"><td class='aqiwtxt' nowrap="true">151-200</td><td class='aqiwtxt' i18n='generic'>Unhealthy</td><td class='aqiwtxt' i18n='generic'>Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects</td><td class='aqiwtxt' i18n='generic'>Active children and adults, and people with respiratory disease, such as asthma, should avoid prolonged outdoor exertion; everyone else, especially children, should limit prolonged outdoor exertion</td></tr><tr style="background-color:#660099;"><td class='aqiwtxt' nowrap="true">201-300</td><td class='aqiwtxt' i18n='generic'>Very Unhealthy</td><td class='aqiwtxt' i18n='generic'>Health warnings of emergency conditions. The entire population is more likely to be affected.</td><td class='aqiwtxt' i18n='generic'>Active children and adults, and people with respiratory disease, such as asthma, should avoid all outdoor exertion; everyone else, especially children, should limit outdoor exertion.</td></tr><tr style="background-color:#7e0023;"><td class='aqiwtxt' nowrap="true">300+</td><td class='aqiwtxt' i18n='generic'>Hazardous</td><td class='aqiwtxt' i18n='generic'>Health alert: everyone may experience more serious health effects</td><td class='aqiwtxt' i18n='generic'>Everyone should avoid all outdoor exertion</td></tr></table></div><br>To know more about Air Quality and Pollution, check the <a href='http://en.wikipedia.org/wiki/Air_quality'>wikipedia Air Quality topic</a> or the <a href='http://www.airnow.gov/index.cfm?action=aqibasics.aqi'>airnow guide to Air Quality and Your Health</a>.<br><br>For very useful health advices of Beijing Doctor Richard Saint Cyr MD, check <a href='http://www.myhealthbeijing.com/'>www.myhealthbeijing.com</a> blog.<br><br></center></div></div></div><center><br><ins class="adsbygoogle" style="display:block"data-ad-client="ca-pub-0281575029452656"data-ad-slot="2455076269"data-ad-format="auto"></ins><script>(adsbygoogle = window.adsbygoogle || []).push({});</script><style type='text/css'>.usage-notice {line-height:1.5;max-width:95%;width:1000px;margin-top:10px;padding:5px;font-size: 15px;background-color:#ffffff;text-shadow: 1px 1px 1px white;-webkit-box-shadow: 1px 1px 8px -3px rgba(0,0,0,0.3);}</style><div class="textshadowwhite usage-notice" style=''><b>Usage Notice</b>: All the Air Quality data are unvalidated at the time of publication, and due to quality assurance these data may be amended, without notice, at any time. 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70px;-webkit-user-select:none; -moz-user-select:none; -ms-user-select: none;}.onoffswitch-checkbox {display: none;}.onoffswitch-label {display: block; overflow: hidden; cursor: pointer;border: 2px solid #004E74; border-radius: 20px;}.onoffswitch-inner {display: block; width: 200%; margin-left: -100%;transition: margin 0.3s ease-in 0s;}.onoffswitch-inner:before, .onoffswitch-inner:after {display: block; float: left; width: 50%; height: 30px; padding: 0; line-height: 30px;font-size: 14px; color: white; font-family: Trebuchet, Arial, sans-serif; font-weight: bold;box-sizing: border-box;}.onoffswitch-inner:before {content: "°C";padding-left: 10px;background-color: #04ADFF; color: #FFFFFF;}.onoffswitch-inner:after {content: "°F";padding-right: 10px;background-color: #04ADFF; color: #FFFFFF;text-align: right;}.onoffswitch-switch {display: block; width: 28px; margin: 1px;background: #FFFFFF;position: absolute; top: 0; bottom: 0;right: 36px;border: 2px solid #004E74; border-radius: 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white;font-variant: small-caps;}#settings-lang .flag {vertical-align: text-bottom;display:inline-block;}#settings-lang select {font-size: 18px;}</style><div id='settingsdiv-outer'><div id='settingsdiv' ><div onclick='settingsMenu.close()' style='cursor:pointer;border-bottom:1px solid #ccccf8;padding-top:12px;'><svg height="24px" viewBox="0 0 512 512" width="24px" style='float:right;fill:white;'><path d="M74.966,437.013c-99.97-99.97-99.97-262.065,0-362.037c100.002-99.97,262.066-99.97,362.067,0 c99.971,99.971,99.971,262.067,0,362.037C337.032,536.998,174.968,536.998,74.966,437.013z M391.782,120.227 c-75.001-74.985-196.564-74.985-271.534,0c-75.001,74.985-75.001,196.55,0,271.535c74.97,74.986,196.533,74.986,271.534,0 C466.754,316.775,466.754,195.212,391.782,120.227z M188.124,369.137l-45.251-45.266l67.876-67.877l-67.876-67.876l45.251-45.267 L256,210.743l67.877-67.892l45.25,45.267l-67.876,67.876l67.876,67.877l-45.25,45.266L256,301.245L188.124,369.137z"/></svg><h2>Settings</h2></div><br><center><div id='settings-lang'>Language Settings: <br><div class='sprite-isprt-web-gb flag'></div><div class='sprite-isprt-web-cn flag'></div><div class='sprite-isprt-web-jp flag'></div><div class='sprite-isprt-web-kr flag'></div><div class='sprite-isprt-web-pl flag'></div><br><select onchange='location.href = this.value'><option value='https://aqicn.org/faq/' selected>English</option><option value='https://aqicn.org/faq/cn/' >简体中文 - Chinese</option><option value='https://aqicn.org/faq/jp/' >日本 - Japanese</option><option value='https://aqicn.org/faq/es/' >español - Spanish</option><option value='https://aqicn.org/faq/kr/' >한국의 - Korean</option><option value='https://aqicn.org/faq/ru/' >русский - Russian</option><option value='https://aqicn.org/faq/hk/' >繁體中文 - Traditional Chinese</option><option value='https://aqicn.org/faq/fr/' >Francais - French</option><option value='https://aqicn.org/faq/pl/' >Polski - Polish</option><option value='https://aqicn.org/faq/de/' >Deutsch - German</option><option value='https://aqicn.org/faq/pt/' >Português - Portuguese</option><option value='https://aqicn.org/faq/vn/' >Tiếng Việt - Vietnamese</option><option value='https://aqicn.org/faq/it/' >Italiano - Italian</option><option value='https://aqicn.org/faq/id/' >bahasa Indonesia - Indonesian</option><option value='https://aqicn.org/faq/nl/' >Nederlands - Dutch</option><option value='https://aqicn.org/faq/fa/' >فارسی - Persian</option><option value='https://aqicn.org/faq/th/' >ภาษาไทย - Thai</option><option value='https://aqicn.org/faq/hu/' >Magyar - Hungarian</option><option value='https://aqicn.org/faq/el/' >Ελληνικά - Greek</option><option value='https://aqicn.org/faq/ro/' >Română - Romanian</option><option value='https://aqicn.org/faq/bg/' >български - Bulgarian</option><option value='https://aqicn.org/faq/ur/' >اردو - Urdu</option><option value='https://aqicn.org/faq/hi/' >हिंदी - Hindi</option><option value='https://aqicn.org/faq/ar/' >العربية - Arabic</option><option value='https://aqicn.org/faq/sr/' >Српски - Serbian</option><option value='https://aqicn.org/faq/bn/' >বাংলা - Bangla</option><option value='https://aqicn.org/faq/bs/' >босански - Bosnian</option><option value='https://aqicn.org/faq/hr/' >hrvatski - Croatian</option><option value='https://aqicn.org/faq/tr/' >Türkçe - Turkish</option><option value='https://aqicn.org/faq/uk/' >українська - Ukrainian</option><option value='https://aqicn.org/faq/cs/' >čeština - Czech</option><option value='https://aqicn.org/faq/be/' >беларускі - Belarusian</option></select></div><br><table><tr><td><center><i>Temperature unit:</i><br><span style='font-size:18px'><span style='display:;' id='settings-temp-label-on'>Celcius</span><span style='display:none;' id='settings-temp-label-off'>Fahrenheit</span></span></center></td><td><div class="onoffswitch" onclick='settingsMenu.click("temp")'><input type="checkbox" name="onoffswitch" class="onoffswitch-checkbox" id="settings-temp" checked ><label class="onoffswitch-label" for="myonoffswitch"><span class="onoffswitch-inner"></span><span class="onoffswitch-switch"></span></label></div></table></center><br></div><div style='display:none;height:0px;' id='settingsdiv-arrow'><div style='width: 0; height: 0; border: 7px solid transparent;top:0px;border-top: 7px solid #fff;position:relative;;margin-left:100px;'></div></div></div><script>function CSettingsMenu(){var self=this;var isInit = false;var timeout = null;var isPopup = false;this.show = function(){log("show!");if (isPopup) {this.close();return;}isPopup = true;$("#settingsdiv-arrow").hide();$("#settingsdiv").show();var pos = $("#footer-settings-img").offset();$("#settingsdiv-outer").css({left: "0px",width: "100%",bottom: "30px"});$("#settingsdiv").css({width: "100%",textAlign: "center",boxSizing: "border-box"});};this.close = function() 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