What is pm2.5? What is smog? How did it come into being? What are the hazards to human beings?

PM2.5 refers to solid particles or droplets with a diameter less than or equal to 2.5 microns in the air, also known as inhalable particles. These particles are very tiny, only one twentieth of the diameter of human hair, invisible to the naked eye, and can float in the air for several days. PM2.5 is different from sulfur dioxide (SO2), nitrogen dioxide (NO2) and other pollution indicators. It is not a single substance, and its source is very complicated. A part of the smoke comes from factories, urban life and motor vehicles, and a large part of it is secondary pollutants produced by photochemical reactions of pollutants such as particulate matter, nitrogen oxides and volatile organic compounds (VOC) in the atmosphere. The main sources are motor vehicle exhaust, petrochemical, medical and spraying exhaust, sulfur dioxide and nitrogen oxides in thermal power plants, soot, lampblack, construction, cement and road dust. The research shows that the atmospheric haze weather mainly comes from PM2.5, which has a strong extinction effect. The main environmental impacts of PM2.5 are: the formation of haze weather, the reduction of atmospheric visibility, the impact on human health, the regional or global problems caused by long-distance transportation, and the impact on climate change.

Haze is a general term for fog and haze. Haze is a weather phenomenon, also known as haze, which means that a large number of tiny dry dust particles, such as dust, sulfuric acid, nitric acid and organic hydrocarbons, float in the air evenly, which makes the air turbid, blurs the vision and deteriorates the visibility. If the horizontal visibility is less than10000m, the sight distance obstacle caused by this non-aqueous aerosol system is called haze or haze.

Pm2.5 is closely related to smog. It has a great influence on the human body. PM2.5 will penetrate the protective structure of respiratory tract, penetrate into bronchi and lungs, directly affect the ventilation function of lungs, induce pulmonary sclerosis, asthma and bronchitis, and lead to cardiovascular diseases; PM2.5 particles can carry viruses, bacteria, radioactive dust and heavy metals in the air, which have a serious impact on respiratory system, cardiovascular system, immune system, fertility, nervous system and heredity. Weaken people's collective resistance and induce the onset of cancer. It seriously hinders the development of children's lung function and accelerates the death of the elderly with weak constitution.

How to protect yourself from the influence of PM2.5? The first is to wear an anti-fog mask when going out in foggy weather. When indoors, in foggy weather, the smog carrying PM2.5 will enter the room through the gap in the window, and indoor catering fumes will lead to indoor air pollution. How to keep the indoor air fresh? How to make yourself less affected by PM2.5? First, clean up the environment at home and use energy-saving doors and windows, because the sealing effect of energy-saving doors and windows is very good, which can reduce the direct entry of outdoor air into the room. Then, install a fresh air system on the window. When you want to change the fresh air, you don't need to open the window, just use the fresh air system. The fresh air system can filter the outside air into the room and make the air in the temple clean.