In this article I review two websites that report real-time air pollution data for China. At the end of the article, I’ve included a glossary of air pollution terms. Refer to the glossary if you are not familiar with the terms used in the review.
This is the most popular air pollution monitoring site on the web. This site brings together and presents air pollution data for hundreds of cities across China. The pollution readings are assembled in a fairly easy to read format. Data include the Air Quality Index (AQI) and six individual pollutant measurements: PM 2.5, PM 10, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide. Atmospheric data are also reported, including temperature, dew point, atmospheric pressure, relative humidity, and wind speed. Readings are updated hourly.
I like aqicn.org. However, I’ve had problems with its search box query. When searching for a city, the search box query doesn’t always return the right result. It can be frustrating.
I don’t like that fact that I do not know exactly where aqicn.org gets each of its pollutant readings from. If you pull up the real-time air pollution readings for a city, you will see in the footer area of the webpage a list of various possible data sources for the readings. However, you do not know which of the sources are being used for each pollutant. Not only that, you do not know how aqicn.org chooses to calculate each pollutant reading. Are readings for the same pollutant from multiple monitoring sites averaged? Or is only the highest reading used? Who knows. This is a major deficiency of the site.
Aqicn.org uses an AQI system development by the U.S. Environmental Protection Agency (EPA). This system uses numerical values that range from 0 – 500. The higher the number, the worse the air quality. Additionally, a color code is assigned to set ranges of AQI values. Each color-code has a written description. Green is good (0-50). Yellow is moderate (51 – 100). Orange is unhealthy for sensitive groups (101 – 150). Red is unhealthy for all (151 – 200). Purple is very unhealthy (201- 300). Maroon is hazardous (301 – 500).
Aqicn.org also follows the U.S. EPA’s method for reporting the AQI for a given place. While aqicn.org reports six different pollutant measurements, only one of those pollutants is used to report the final AQI for a given place. The individual pollutant with the highest AQI is used for the final AQI number. As such, you will notice that the AQI for Chinese cities is almost always the same as the PM2.5 reading. It is the large number of small particulates in China’s ambient air that most often results in the highest AQI and, therefore, the most serious health risk.
Aqicn.org has air pollution readings for countries all around the globe. It’s a great site. However, I am disappointed that I do not know exactly where the data comes from and if the data is accurate.
For more information about the U.S. EPA’s AQI system, click on these two links:
This website reports the Air Quality Index (AQI) and the six different air pollutants used to calculate the AQI: PM 2.5, PM 10, carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2). Currently, pm25s.com reports data for 190 cities in China.
The pollution data are presented in easy to read tables. For example, here are readings for Anyang City, where I am currently living:
I’m uncertain as to how often the readings are updated. From my use of the website, it seems like readings are updated every two hours.
A small shortcoming of pm25s.com is that it does not have a query box to search by city. Instead of having a query box, all 190 cities are organized by province and listed alphabetically on the front page of the website. Also, the data set of only 190 cities is rather limited.
PM25s.com uses a color-coded scale developed by China’s Ministry of Environmental Protection (MEP). As with the U.S. EPA’s scale, each color corresponds to a set range of AQI readings. However, China’s MEP and the U.S. EPA differ in how they compute the AQI number and how they describe each color-coded category. The AQI system used by China’s MEP has been criticized for misrepresenting the severity of the air pollution and the attendant health risks.
PM25s.com clearly states that all of its pollution data comes from China’s Ministry of Environmental Protection.
For a detailed analysis of how the U.S. EPA AQI and the China MEP AQI differ, click on these links:
Glossary of Air Pollution Terms
AQI – Air Quality Index. This is an overall score for air quality. The AQI is calculated using six different pollution measurements: carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), PM 2.5, and PM 10.
CO – carbon monoxide, a poisonous gas.
MEP – The Ministry of Environment Protection. The MEP is China’s governmental organization responsible for monitoring and protecting China’s air, soil, and water. On the web at http://english.mep.gov.cn/
NO2 – nitrogen dioxide, a toxic gas that can be harmful to the respiratory system.
ozone – a toxic gas that can irritate, inflame, and damage the respiratory system.
PM 2.5 – particulate matter of 2.5 micrometers or less in diameter. This is a measure of small particles present in the air. These tiny particulates can lodge deep in lung tissue and cause respiratory issues. Long term exposure to these small particulates has been linked to lung cancer.
PM 10 – particulate matter of 10 micrometers or less in diameter.
SO2 – sulfur dioxide, a toxic gas that can damage living tissues and cause respiratory issues.