Why is the air quality index of American consulate different from that of EPA?

First of all, the US Embassy has only one monitoring point, while the Environmental Protection Agency has many atmospheric monitoring points, and the pollution index released is also general (possibly weighted). Therefore, from the perspective of monitoring, it is reasonable for the government to refute the data of the US Embassy. I just overreacted.

In addition, the controversial PM2.5 method used by the US Embassy to monitor particulate matter is the β -ray attenuation method, which measures the amount of particulate matter based on the blocking of radiation by particulate matter in the air. In China, the national standard is the quality method, that is, collecting and weighing the mass of particulate matter to measure. Therefore, different methods will naturally bring about differences in data.