Air Quality Index and Air Pollution Index

The air pollution index is divided into 7 categories: 0–50, 51–100, 101–150, 151–200, 201–250, 251–300, and above 300. These correspond to 7 levels of air quality; the higher the index, the higher the level, indicating more severe pollution and a more significant impact on human health. The air pollution index is 0–50, the air quality level is Class I, and the air quality is considered excellent. At this time, there is no air pollution issue, and it poses no harm to the public’s health. The air pollution index ranges from 51 to 100, the air quality level is II, and the air quality is considered good. At this time, air quality is considered acceptable, and it poses no threat to public health except for a very small number of people who are particularly sensitive to certain pollutants. The air pollution index ranges from 101 to 150, with the air quality level classified as III(1); the air quality is considered to be slightly polluted. At this time, people who are more sensitive to pollutants, such as children and the elderly, those with respiratory or heart diseases, as well as those who enjoy outdoor activities, will see their health affected, while it has little impact on healthy people. The air pollution index ranges from 151 to 200, the air quality level is III(2), and the air quality condition is classified as mild pollution. At this time, the health of almost everyone will be affected, with particularly pronounced adverse effects on sensitive individuals. The air pollution index ranges from 201 to 300, with the air quality grades being IV(1) and IV(2); the air quality condition is classified as moderate to moderately severe pollution. At this time, everyone's health will be significantly affected. When the air pollution index is greater than 300, the air quality level is classified as Grade V, indicating severe air pollution. At this point, everyone's health will be severely affected. The air pollution index can alert the general public, especially those who are sensitive to air pollution such as people with heart disease or respiratory conditions, to take preventive measures when necessary.

That’s very detailed. I’m not sure what kind of pollutants this pollution index measures – are they pollution particles? Isn’t it common these days to use PM2.5 or PM5 as standards?

:I don’t know about L either; that’s what it says on Baidu. But I don’t think it’s pollution particles

The Air Pollution Index (API) is a value that simplifies the concentrations of several commonly monitored air pollutants into a single conceptual index, which is used to classify the degree of air pollution and the quality of the air. It is suitable for indicating the short-term air quality conditions and trends in cities. Pollutants of air pollution include: soot, total suspended particulates, inhalable suspended particulates (dust), nitrogen dioxide, sulfur dioxide, carbon monoxide, ozone, volatile organic compounds, and so on.

Technical Specifications for Ambient Air Quality Index (AQI) (Trial) (HJ 633—2012)

The air pollution index is divided into 7 categories: 0–50, 51–100, 101–150, 151–200, 201–250, 251–300, and above 300. These correspond to 7 levels of air quality; the higher the index, the higher the level, indicating more severe pollution and a more significant impact on human health. The air pollution index is 0–50, the air quality level is Class I, and the air quality is considered excellent. At this time, there is no air pollution issue, and it poses no harm to the public’s health. The air pollution index ranges from 51 to 100, the air quality level is II, and the air quality is considered good. At this time, air quality is considered acceptable, and it poses no threat to public health except for a very small number of people who are particularly sensitive to certain pollutants. The air pollution index ranges from 101 to 150, with the air quality level classified as III(1); the air quality is considered to be slightly polluted. At this time, people who are more sensitive to pollutants, such as children and the elderly, those with respiratory or heart diseases, as well as those who enjoy outdoor activities, will see their health affected, while it has little impact on healthy people. The air pollution index ranges from 151 to 200, the air quality level is III(2), and the air quality condition is classified as mild pollution. At this time, the health of almost everyone will be affected, with particularly pronounced adverse effects on sensitive individuals. The air pollution index ranges from 201 to 300, with the air quality grades being IV(1) and IV(2); the air quality condition is classified as moderate to moderately severe pollution. At this time, everyone's health will be significantly affected. When the air pollution index is greater than 300, the air quality level is classified as Grade V, indicating severe air pollution. At this point, everyone's health will be severely affected.

Take your time to look carefully; don’t get stuck in details