Fine particulate matter, also known as fine particles, fine particles, PM2.5, refers to particulate matter in the ambient air with an aerodynamic equivalent diameter less than or equal to 2.5 microns. 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 the air pollution is represented. Although PM2.5 is only a small component of the Earth’s atmospheric composition, it has an important impact on air quality and visibility, among other things. Compared with coarser atmospheric particles, PM2.5 has a small particle size, large area, strong activity, and is easily accompanied by toxic and harmful substances (e.g., heavy metals, microorganisms, etc.), and has a long residence time and long transport distance in the atmosphere, thus having a greater impact on human health and the quality of the atmospheric environment. Natural sources Include soil dust (containing oxide minerals and other components) sea salt (the second largest source of particulate matter, with a composition similar to that of seawater), plant pollen, spores, bacteria, etc. Catastrophic events in nature, such as volcanic eruptions that emit large amounts of volcanic ash into the atmosphere, forest fires or bare coalfield fires and dust storm events can transport large amounts of fine particulate matter into the atmosphere. Anthropogenic sources Anthropogenic sources include stationary sources and mobile sources. Stationary sources include various fuel combustion sources, such as power generation, metallurgy, petroleum, chemical, textile printing and dyeing, and other industrial processes, heating, cooking process of coal and gas or fuel oil emissions of soot. Mobile sources are mainly exhaust emissions to the atmosphere from the use of fuel in the operation of various types of transportation. Hazard Introduction Although fine particulate matter is only a small component of the Earth’s atmospheric composition, it has an important impact on air quality and visibility, among other things. Compared with the coarse atmospheric particles, fine particles are small in size, rich in a large number of toxic and harmful substances and long residence time in the atmosphere, long transport distance, and therefore have a greater impact on human health and the quality of the atmosphere. Studies have shown that the smaller the particles, the greater the risk to human health. Fine particulate matter can float to farther places, so the impact range is larger. Fine particulate matter is more dangerous to human health because the smaller the diameter, the deeper it enters the respiratory tract. 10μm diameter particles are usually deposited in the upper respiratory tract, and those below 2μm can penetrate into the fine bronchi and alveoli. After fine particles enter the body to the alveoli, they directly affect the ventilation function of the lungs and make the organism easily in a state of oxygen deficiency. Damage to organs Long-term exposure to particles can cause cardiovascular and respiratory diseases as well as lung cancer. When the concentration of PM2.5 in the air is higher than 10 for a long period of time, it brings an increased risk of death. For every 10 increase in concentration, the overall risk of death increases by 4%, the risk of death from heart and lung disease increases by 6%, and the risk of death from lung cancer increases by 8%. In addition, PM2.5 is very easy to adsorb organic pollutants such as polycyclic aromatic hydrocarbons and heavy metals, making the chances of cancer, teratogenic and mutagenic significantly higher. Prevention methods 1, filtration method, including air conditioners, humidifiers, air fresheners, etc., the advantage is to significantly reduce the concentration of PM2.5, the disadvantage is that the filter membrane needs to be cleaned or replaced. 2, water adsorption ultrasonic atomizer, indoor water curtain, pool, fish tank, etc., can absorb hydrophilic PM2.5 in the air, the disadvantage is to increase the humidity, hydrophobic PM2.5 can not be effectively removed. 3, plant absorption method plant leaves have a large surface area, can absorb harmful gases and adsorption PM2.5, the advantage is that it can produce favorable gas, the disadvantage is that the absorption efficiency is low, some plants will produce harmful gases. Life response 1, hazy weather less open windows, it is best not to go out or morning exercise hazy weather does not advocate opening windows in the morning and evening ventilation, it is best to wait for the moon to come out and then open the window ventilation. Hazy weather is a “dangerous day” for patients with cardiovascular disease, especially the elderly with respiratory and cardiovascular diseases, foggy days are best not to go out, more should not be morning exercise, otherwise it can trigger the disease, and even heart attack, causing life-threatening. The reason why foggy days are “dangerous days” for patients with cardiovascular disease is because of the high pressure of fog, the oxygen content in the air is elevated, people can easily feel chest tightness, the morning damp and cold fog will also cause cold stimulation, which can easily lead to esophageal spasm, blood pressure fluctuations, increased heart load, etc.. At the same time, some pathogens in the fog can cause headaches and even induce hypertension, cerebral hemorrhage and other diseases. Therefore, people with cardiovascular disease, especially the elderly and frail, should not go out in the foggy days, and not in the foggy days of morning exercise, in order to avoid the danger. 2, go out to wear professional dust masks General conventional masks will not play a role because the particles are too small, KN90, KN95, N95 level dust masks to effectively filter such fine particles, but also to choose a suitable mask for yourself, to avoid the leak around the non-tight fit. In addition, when you return from going out, you should wash your face and bare skin immediately. The better anti-PM2.5 masks are mainly filters rather than masks, such as masks with activated carbon filters and medical masks are unable to prevent PM2.5. 3, drink more tung kung fu tea, tung ginseng tea, tung kung fu granules, tung kung fu soup and other “lung dust removal” tea tung kung fu tea has a clear fire filter lung dust function, can strengthen the ability of alveolar cells to discharge toxic fine particles, can assist the body to discharge the accumulation of PM2.5 particles and other harmful substances in the body. 4, a small amount of vitamin D supplementation winter fog, sunlight less, due to too little ultraviolet radiation, vitamin D generation in the human body is insufficient, some people will also produce mental depression, depression and other phenomena, when necessary, you can supplement some vitamin D. 5, light diet and drink more honey water foggy days, the diet should choose light and easy to digest and vitamin-rich food, drink more water, eat more fresh vegetables and fruits, which can not only supplement A variety of vitamins and inorganic salts, but also to moisten the lungs in addition to dryness, expectorant cough, spleen and kidney role. Eat less stimulating food, eat more pears, loquats, oranges, tangerines and other foods. 6, deep cleaning The human surface of the skin directly in contact with the outside air, it is easy to be harmed by the haze weather. Especially in the busy and noisy ten “haze” in the city, in addition to the haze at any time to deal with the danger of “muscle”, due to construction, car exhaust, industrial fuel combustion, burning fireworks candles and other reasons caused by suspended particles, inevitably clogged in the pores to form Blackheads, causing pore blockage, keratin build-up, skin peeling and other skin problems, so the first measure of self-protection is to deep clean the skin surface, clean pores. 7, try to reduce smoking or even not smoking Smoke has a lot of PM2.5, will have a direct and indirect harm to the human body. If you can’t stop the people around you from smoking, then you should try to stay away from the smoke.