First of all, we understand what is PM2.5, PM is the English abbreviation for atmospheric particulate matter, PM2.5 is the aerodynamic diameter of particulate matter less than 2.5 μm, also known as fine particulate matter, in recent years, China’s haze weather is the main culprit in the formation of the main. PM2.5 particle size is small, the surface area is large, the composition is complex, easy to enrich the toxic and harmful substances in the air, such as organic (such as polycyclic aromatic hydrocarbons), inorganic (such as sulfates, nitrates, etc.) and heavy metals. Inorganic substances (such as sulfate, nitrate, etc.) and heavy metals, the larger particles can only be planted in the upper respiratory tract, but fine particles can enter the alveolar depths with the respiratory can enter the circulatory system through the respiratory membrane, the human body caused damage to a number of systems. Studies have shown that exposure to PM2.5 significantly increases respiratory diseases, cardiovascular diseases, cancers, and even fetal dysplasia, and that the longer the exposure time, the greater the damage. We can understand PM2.5 through data: a foreign literature review study found that for every 10μg/m3 increase in PM2.5 concentration, the total cause of death and cardiovascular disease deaths increased by 6% and 11%, respectively, and the risk of deaths from cardiopulmonary diseases increased by 6%, and the risk of deaths from lung cancer increased by 8%. In addition, PM2.5 is very easy to adsorb organic pollutants such as polycyclic aromatic hydrocarbons and heavy metals, so that the chances of carcinogenicity, teratogenicity, mutation significantly higher. The World Health Organization considers fine particulate matter less than 10 to be a safe value, and you can see which standard PM2.5 is on in your region according to the air quality level of the daily weather forecast: First of all, let’s look at cardiovascular disease: a foreign study on short-term exposure to PM2.5 showed that short-term exposure is positively correlated with the increase in the risk of all-cause mortality, cardiovascular deaths, and hospitalization, and that for every 10 μg/m3 of elevated PM2.5 concentration, the cardiovascular risk increases by 10 μg/m3. For every 10 μg/m3 increase in PM2.5 concentration, the cardiovascular mortality and hospitalization rates increased by 0.8% and 0.9%, respectively, and the increase in mortality rates varied considerably in different regions. A monitoring study of PM2.5 in Beijing showed that the average PM2.5 concentration during the study period was 96.2 μg/m3, and it was found that for every 10 μg/m3 increase in PM2.5 concentration, the incidence of ischemic heart disease on the same day increased by 0.27% and the mortality rate increased by 0.25%. A study in Minhang District, Shanghai, showed that the same-day concentration of PM2.5 had the greatest impact on the daily mortality rate of cardiovascular and cerebrovascular diseases, with a 0.87% increase in cardiovascular and cerebrovascular disease mortality rate for every 10 μg/m3 increase in its concentration. A study by the European ESCAPE program found that for every 5 μg/m3 increase in PM2.5 concentration, the risk of coronary events increased by 13%, and remained positively correlated when PM2.5 concentrations were below the European annual average concentration limit (25 μg/m3). Second, respiratory diseases: a study explored the relationship between air pollution and lung cancer incidence and mortality in China. meta-analysis of the results of 21 cohort studies found that for every 10 μg/m3 increase in PM2.5, the risk of death from lung cancer increased by 7.23%. there was a direct correlation between the incidence of respiratory diseases and mortality from 2004-2009 in Beijing with PM2.5 exposure, which It was found that in severe cases, for every 10μg/m3 increase in PM2.5, the mortality and morbidity of respiratory diseases increased by 4.60% and 4.48%, respectively, which was much higher than the average and had obvious seasonality, and the increase in mortality and morbidity of lung cancer was most obvious in winter. The increase in PM2.5 concentration is also significantly correlated with the incidence of respiratory infections, asthma, allergic rhinitis, and chronic obstructive pulmonary disease (COPD). The main protection for PM2.5 is to minimize going out in severely polluted weather, install air purifiers at home, go out when the air quality is poor and pay attention to bring anti haze masks, don’t go out to exercise on foggy days, and reduce indoor smoking.