What is the value of pm2.5? No outdoor activities.

There is no clear definition at present. Generally, moderate pollution should not be exercised outdoors, but it is not to the extent of prohibition. Smog weather is a "health killer" for patients with cardiovascular diseases, especially the elderly with respiratory diseases and cardiovascular diseases. It is best not to go out in foggy days, and it is not suitable for morning exercise, otherwise it may induce diseases and even heart attacks, which may be life-threatening.

PM2.5: Fine particles are also called fine particles, fine particles and PM 2.5 ... Fine particles mean that the aerodynamic equivalent diameter in the ambient air is less than or equal to 2.5? Micron particles. It can be suspended in the air for a long time, and the higher its concentration in the air, the more serious the air pollution.

Although PM2.5 is only a small part of the composition of the earth's atmosphere, it has an important impact on air quality and visibility. Compared with atmospheric coarse particles, PM2.5 has small particle size, large area, strong activity, easy attachment of toxic and harmful substances, long stay in the atmosphere and long transportation distance, so it has a great impact on human health and atmospheric environmental quality.

Prevention method: 1, filtration method. 2, water absorption method, 3, plant absorption method.