According to the new air quality standard of PM2.5 testing network, the 24-hour average standard value distribution "excellent" for 0~35μg/m?, "good" for 35~75μg/m?.
According to the World Health Organization (WHO) 2005 Air Quality Guidelines (AQGs), the guideline values are
PM2.5:
Fine particulate matter, also known as fine particles, fine particles, PM2.5, refers to particulate matter in the ambient air that has an aerodynamic equivalent diameter of less than or equal to 2.5?micrometers. It can be suspended in the air for a longer period of time, and the higher the concentration of its content in the air, the more serious air pollution is represented. Although PM2.5 is a very small component of the Earth's atmospheric composition, it has a significant impact on air quality and visibility. Compared with coarser atmospheric particulate matter, PM2.5 has a small particle size, large area, strong activity, and is prone to carry toxic and harmful substances (e.g., heavy metals, microorganisms, etc.), as well as a long residence time in the atmosphere and a long transport distance, thus having a greater impact on human health and the quality of the atmospheric environment.
The current standard for PM2.5 in China:
Reference
Fine particulate matter_Baidu Encyclopedia ：/item/%E7%BB%86%E9%A2%97%E7%B2%92%E7%89%A9/804913?fr=aladdin&. fromid=353332& fromtitle=PM2.5