The U.S. Consulate in Chengdu operates an air quality monitor to measure PM 2.5 particulates as an indication of the air quality in the area surrounding its Lingshiguan Road offices. Pollutants such as particle pollution are linked to a number of significant health effects — and those effects are likely to be more severe for sensitive populations, including people with heart or lung disease, children, and older adults. This monitor is a resource for the health of the American community. Citywide analysis cannot be done, however, on data from a single machine.
Particulates less than 2.5 micrometers in diameter (PM 2.5) are referred to as “fine” particulates and are believed to pose the largest health risks. PM 2.5 is a standard recognized by the U.S. Environmental Protection Agency (EPA) and allows us to compare against U.S. standard measures. PM 2.5 particulates are of concern since they are small enough to directly enter the lungs and even the blood stream. For more information, please visit the EPA site.
The U.S. EPA has developed a formula to convert PM 2.5 readings into an air quality index (AQI) value that can help inform health-related decisions. For example, an AQI value of 50 or below represents good air quality with little potential to affect public health, while an AQI value over 300 represents hazardous air quality. Please note that AQI is different from the Air Pollution Index (API) used in China. For more information on AQI and how it is calculated, please click here.
The monitor’s measurements, expressed in the form of PM 2.5 concentration (micrograms per cubic meter, µg/m3) and corresponding AQI, are available at http://twitter.com/cgchengduair.
|Air Quality Index Levels of Health Concern||Numerical Value||Meaning|
|Good||0 to 50||Air quality is considered satisfactory, and air pollution poses little or no risk|
|Moderate||51 to 100||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.|
|Unhealthy for Sensitive Groups||101 to 150||Members of sensitive groups may experience health effects. The general public is not likely to be affected.|
|Unhealthy||151 to 200||Everyone may begin to experience health effects; members of sensitive groups may experience more serious health effects.|
|Very Unhealthy||201 to 300||Health warnings of emergency conditions. The entire population is more likely to be affected.|
|Hazardous||301 to 500||Health alert: everyone may experience more serious health effects.|