Which air quality index app data is accurate?

Reasons for data differences

Different sources.

In China, there are two sources of authoritative air quality index data. One is my country’s main environmental monitoring station, including monitoring substations in various places, and the other is the monitoring data of the US Embassy.

The former data is mainly evaluated based on the standards set by China, while the latter data is mainly based on internationally accepted standards and those used by the United States.

The U.S. Embassy’s data is mainly used to serve U.S. residents working and living in China.

China’s air quality evaluation standards are relatively low compared to international standards. Foreign countries define 0-35 as good air quality, while the domestic standard is 0-50.

During the air quality index calculation process, at the same concentration, the ambient air quality standards are different, and the AQI calculation results are different.

For example, for PM2.5, the 24-hour average concentration limit in the United States is 35 micrograms/cubic meter, while in China it is 75 micrograms/cubic meter. For the same pollutant concentration, the calculated AQI index differs by nearly one degree. times.

Some weather applications use data from Chinese monitoring stations, while others use American data, which results in different data reported by different weather applications.

The value points are different.

The air quality index has different value points. According to national standards, the data at each point should be referenced and the daily average value should be used.

However, some applications use hourly values ??or maximum values ??per unit point, which will lead to "data fights" in weather applications.

The basis is different.

According to analysis by relevant personnel of the Environmental Monitoring Center, some applications publish AQI index mainly based on PM2.5 value, which is only one of the index evaluation standards, so when the concentration of other pollutants such as ozone (O3) exceeds the standard , it is inevitable that there will be inconsistencies with the data released by the environmental protection department.

Which one is more reliable?

Based on the above analysis, no application is accurate, and the data of each application will be biased.

If you want to refer to the most accurate data, you should directly pay attention to the real-time data released by the China Environmental Monitoring Station, or pay attention to the data released by the US Consulate.

China Environmental Monitoring Station has launched an official App, but it is not as "humanized" as other commercial Apps. The functions of the latter are more complete than the former and can give users a better experience.

Therefore, when using a weather app to understand air quality, you may wish to use two or three apps together to verify each other and obtain more accurate data.