According to the proportion of various components in the air, the Air index simplifies the monitored air concentration into a single conceptual index value, and indicates the degree of air pollution and air quality in grades, which is suitable for expressing the short-term air quality status and changing trend in cities.
The range of air pollution index is 0 ~ 500, where 0 ~ 50,51~100,10/~ 200,201~ 300, which are greater than 300, respectively, corresponding to the national air quality standards.
In practical application, III and IV are divided into III (1), III (2), IV (1) and IV (2).
First class, the air quality evaluation is excellent, and it has no impact on human health; Grade II, with good air quality evaluation and no obvious impact on human health; Grade III, mild pollution, and irritating symptoms in healthy people; Grade Ⅳ, moderate pollution, and irritating symptoms generally appear in healthy people; Grade V, seriously polluted, with severe irritation to healthy people.
Extended data:
When the air pollution index reaches light pollution (i.e. 100 ~ 200), healthy people may have irritating symptoms, and patients with heart disease and respiratory diseases should reduce physical exertion and outdoor activities; When the air pollution index reaches 200 ~ 300, healthy people generally have symptoms, and the elderly and patients with heart disease and lung disease should stay indoors to reduce physical activity;
Healthy people should also avoid outdoor activities when they reach severe pollution (that is, the air pollution index is above 300).
It classifies the degree of air pollution and air quality status, and is suitable for expressing the short-term air quality status and changing trend of cities.
Air quality sub-indices are also specified for individual pollutants. The main pollutants involved in air quality assessment are fine particles, inhalable particles, sulfur dioxide, nitrogen dioxide, ozone and carbon monoxide.
Baidu Encyclopedia-Air Quality Index