Last Saturday's weather forecast

Last Saturday, the light rain turned cloudy, and now the smog is so serious, the harm of smog.

Affect your health. The composition of smog is very complex, including hundreds of atmospheric particles. Among them, aerosol particles with a diameter less than 10 micron are harmful to human health, such as mineral particles, sea salt, sulfate, nitrate and organic aerosol particles. Aerosol particles with a diameter less than 10 micron are coarse particles, and those with a diameter less than 2.5 microns are usually called fine particles, which can be inhaled into the lungs, and can directly enter and adhere to the upper and lower respiratory tract and lung lobes of the human body. Because most atmospheric aerosols in smog can be inhaled by human respiratory tract, especially submicron particles will be deposited in upper respiratory tract, lower respiratory tract and alveoli respectively, causing diseases such as rhinitis and bronchitis, and long-term exposure to this environment will also induce lung cancer. In addition, because ultraviolet rays in sunlight are the only way for human body to synthesize vitamin D, the weakening of ultraviolet radiation directly leads to the high incidence of rickets in children. In addition, ultraviolet light is the main weapon to kill atmospheric microorganisms such as bacteria and viruses in nature. Hazy weather leads to the weakening of ultraviolet rays in the surface layer, which is easy to enhance the activity of infectious bacteria in the air and increase infectious diseases.

2. Affect mental health. Hazy weather is easy to make people feel pessimistic. If it is not adjusted in time, it will easily get out of control.

3. Affect traffic safety. When there is haze weather, outdoor visibility is low, pollution continues, traffic jams and accidents occur frequently.

4. Affect the regional climate. Regional extreme weather events occur frequently and meteorological disasters occur one after another. What is even more worrying is that smog has also accelerated the early arrival of photochemical smog pollution in cities. Photochemical smog is a kind of light blue smog. Automobile exhaust and factory exhaust contain a lot of nitrogen oxides and hydrocarbons. These gases will undergo photochemical reactions under the action of sunlight and ultraviolet rays, resulting in photochemical smog. Its main components are a series of oxidants, such as ozone, aldehydes and ketones. It is very toxic and has a strong stimulating effect on the human body. In severe cases, there will be dyspnea, decreased vision, hand and foot convulsions and so on. Choose an anti-fog mask, one depends on the standard and the other on the filtration efficiency. The United States imports Puweixin Tmall

Speaking of standards, people are most familiar with the N90 and N95 series masks of 3X brand, both of which are named after NIOSH standard. In addition to NIOSH standard, ASTM standard of American Society for Testing Materials, KN standard of China and FFP standard of Europe are all universal and can be used to measure important indicators of masks.

Among the indicators of masks, everyone is most concerned about the filtration efficiency of particulate matter. Therefore, before purchasing masks, you can learn more about the particle filtration efficiency corresponding to various standards. "N95" in NIOSH means that the filtration efficiency of particles as small as 0.3 micron reaches 95%. In fact, the highest standards of ASTM and FFP require higher particle filtration efficiency than NIOSH N95. For example, the ASTM standard requires a filtration efficiency of 98% for particles as small as 0. 1 micron.