The average annual concentration of PM2.5 less than 10 is a safe value; The World Health Organization also pointed out in the 2005 edition of the Air Quality Guide that when the average annual concentration of PM2.5 reaches 35 μ g/m3, compared with the situation of 10 μ g/m3, the risk of human death will increase by about 15%.
The annual and 24-hour average concentration of PM2.5 is less than 25, which is a safe value. The World Health Organization also pointed out in the 2005 edition of the air quality guidelines that when the hourly average concentration of PM2.524 exceeds 25 μ g/m3, it will increase by 10 μ g per m3, and the mortality rate will increase by about 5%.
Three-level transition standard: 75 micrograms per cubic meter
Secondary transition standard: 50 micrograms per cubic meter
Level 1 transition standard: 35 micrograms per cubic meter.
Air quality standard value AQG standard: 25 micrograms per cubic meter
For details, please refer to the official website of WHO.