About the World Air Quality Index project
aqicn.org - waqi.info

The World Air Quality Index project is a non-profit project started in 2007. Its mission is to promote air pollution awareness for citizens and provide a unified and world-wide air quality information.

The project is providing transparent air quality information for more than 130 countries, covering more than 30,000 stations in 2000 major cities, via those two websites: aqicn.org and waqi.info.
The founding team, located in Beijing China, is composed of several contributors in the domain environmental sciences, system engineering, data science, as well as visual design. The team has been expanding worldwide, with new key supporters from Singapore, India, Australia, USA.

The project, despite its social intent and expensive outreach, has never received any public funding. The limited income, essentially from online ads, is used to cover the infrastructure and hardware cost. Engineering work is contributed.

The project is constantly looking for support from more contributors. It has now received active contributions from more than 14883 citizens from 132 countries:

made in 北京


If you would like to send us a message, please try to use one of the following dedicated contact channels:

If none of the above channels match your need, click here to send us a message (but, please, keep in mind that due to our limited team capacity we can not guarantee replying to all messages).


我们 必须 感谢 美国驻北京大使馆 最先 为大家 提供了PM2.5检测数据。 我们 也要 非常 感谢 中国 环保局 在中国主要城市中 为大家 提供了 数百个的 PM2.5监测站 所付出的巨大努力。

All this work is made possible thanks to the excellent work for the worldwide EPA (below list not exhaustive):


We are looking for help to translate this website. More information, please check the translation page.

Common question & answers

  1. Air Quality Data sources: All the Air Quality data seen on World Air Quality Index are the official data from each country respective Environmental Protection Agency (EPA). Data from each EPAs is measured using professional monitoring equipment. The full EPA source list used in World Air Quality Index is available from sources page.
  2. Seeing different readings from other websites: This is most likely normal, and due to the fact that different websites use different AQI scales present the data. At World Air Quality Index, we are using the US EPA scale, while other website might use different scales. Check this article for more information.
  3. I want to monitor the air quality in my area: As high-end professional stations can be really expensive (more than $10K per stations), the World Air Quality Index project / Earth Sensing Labs has designed specialy optimized and affordable monitoring stations costing as low as $200. Please check the GAIA air quality monitoring station product page.
  4. I want to add a new station on the map: Provided your monitoring station is qualified (for instance if it is using BAM, TOEM or GAIA technology), then adding a new station on the map is not only simple and straightforward but also completely free. Please refer to this page for the full explanation
  5. Data quality & real-time validation: The data published on World Air Quality Index is real-time and therefore unvalidated at the time of publication. In order to strengthen the quality, a set of real-time AI algorithms are used to detect abnormal data conditions (sparks, low reporting, etc.) and automatically 'disable' data reported from defective stations.
  6. Historical data access: We are currently investigating with several international institutions (WHO, UN, GEO) the possibility to setup a framework for accessing the historical Air Quality data. If you are from an international institution, organization or university and want to join this effort, then check our data platform page.
  7. API (Application Programing interface): The World Air Quality Index project is offering a free API for maps, tiles and programatic JSON access. Check the API page for more information.
  8. Contributing to the World Air Quality Index project: The project is always looking for more hands to support the activities: For instance, to write articles, to improve our applications, to create new data visualization, to improve the air quality forecast or to translate the website and app to news languages. Check the contribute page for more info.
  9. Fundings: The World Air Quality Index project is independent from any governement and any "profit" corporation. It has so far not received any fundings from any public nor private entity. The limited income from online ads is used to cover infrastructure cost.
  10. Why chosing the U.S. EPA index to harmonize the data? This is mostly for historcal reason: When we started in 2007, there was not so many alternative, and the US EPA was actually quite proactive at promoting the idea of clean air, so the choice was natural. Some alternatives, such as the European “Common Air Quality Index” could also have been a good option, but the EEA failed to promote their standard. This won't be a problem for long anyways, since we are now working on a improvement which will allow users to select any scale they want among a list of more than 80 scales!
  11. How many cities do you currently provide air quality data for and is the info available on your app in each of them? We are providing the data for 9000 stations worldwide ~ that’s around 600 major cities in 70 countries. The info is available in the app for each of them, but not all of the cities have the “full” set of pollutant monitoring (e.g. PM2.5, PM10, Ozone, NO2, SO2, CO). For example, some only have PM10 or a composite AQI. We are also continuously increasing the coverage, targeting to get 10 to 20% more stations every year. The full list of cities and stations is available from this page.
  12. Media kit? Our public media kit is available from the media kit page.
Any other question, please check the Frequently Asked Question page.

made in 北京



本网站采用的污染指数和颜色与EPA是完全相同的。 EPA的指数可以从 AirNow上查到

空气质量指数 空气质量指数级别(状况)及表示颜色 对健康影响情况 建议采取的措施
0 - 50 一级(优) 空气质量令人满意,基本无空气污染 各类人群可正常活动
51 -100 二级(良) 空气质量可接受,但某些污染物可能对极少数异常敏感人群健康有较弱影响 极少数异常敏感人群应减少户外活动
101-150 三级(轻度污染) 易感人群症状有轻度加剧,健康人群出现刺激症状 儿童、老年人及心脏病、呼吸系统疾病患者应减少长时间、高强度的户外锻炼
151-200 四级(中度污染) 进一步加剧易感人群症状,可能对健康人群心脏、呼吸系统有影响 儿童、老年人及心脏病、呼吸系统疾病患者避免长时间、高强度的户外锻炼,一般人群适量减少户外运动
201-300 五级(重度污染) 心脏病和肺病患者症状显著加剧,运动耐受力降低,健康人群普遍出现症状 儿童、老年人及心脏病、肺病患者应停留在室内,停止户外运动,一般人群减少户外运动
300+ 六级(严重污染) 健康人群运动耐受力降低,有明显强烈症状,提前出现某些疾病 儿童、老年人和病人应停留在室内,避免体力消耗,一般人群避免户外活动
(参考详见 http://zh.wikipedia.org/wiki/空气质量指数)

如果你想了解更多有关空气质量与污染,详见维基百科或者 AirNow

有关健康建议详见北京的Richard Saint Cyr MD医生的博客:www.myhealthbeijing.com

注意事项: 所有空气质量数据在发布时均未经验证,并且为了保证数据质量,这些数据可能随时被修改,恕不另行通知。 世界空气质量指数项目在编制此信息的内容时已经运用了所有合理的技能和谨慎,在任何情况下世界空气质量指数项目团队或其代理人将不会为由于提供此数据而直接或间接引起的伤害、合同损失、侵权及其他任何损失负责。



Temperature unit: