What is the measure of weather quality?

according to the environmental protection law of the people's Republic of China and the law of the people's Republic of China on the prevention and control of air pollution, China began to implement the ambient air quality standard on October 1, 1996. This standard divides the relevant areas into three types according to their functions: the first type is nature reserves, forest areas, scenic spots and other areas that need special protection, the second type is residential areas, mixed commercial and traffic areas, cultural areas, general industrial areas and rural areas, and the third type is specific industrial areas. Ambient air quality standards are also divided into three levels, the first level standard is implemented in the first category, the second level standard is implemented in the second category, and the third level standard is implemented in the third category. To measure the level of air quality in a certain area is mainly to see the concentration of various pollutants such as total suspended particulate matter, sulfur dioxide and nitrogen oxides in the air in this place.