Refers to particulate matter in the ambient air with an aerodynamic equivalent diameter of 2.5 microns or less, also known as fine particulate matter. It can be suspended in the air for a long time, and the higher its content (concentration) in the air, the more serious the air pollution.
PM2.5 refers to particulate matter with a diameter less than or equal to 2.5 microns in the atmosphere, also known as lung particles. Its diameter is less than 1/20 of the thickness of a human hair. Although PM2.5 is only a small component of the Earth's atmospheric composition, it has an important impact on air quality and visibility. Compared with coarser atmospheric particles, PM2.5 has small particle size, large specific surface area, strong activity, easy to attach toxic and harmful substances (for example, heavy metals, microorganisms, etc.), and has a long residence time in the atmosphere and a long transport distance. Therefore, it has a greater impact on human health and the quality of the atmospheric environment.
Indoors, secondhand smoke is the most important source of particulate matter. The source of the particulate matter is incomplete combustion, so as long as it is a burning tobacco product, it will produce particles with serious harm. The use of better quality cigarettes is only the self-comfort of the smoker.
World Health Organization first identified PM2.5 carcinogenic
2013.10.17, the World Health Organization's International Agency for Research on Cancer released a report that first identified air pollution as a cause of cancer in humans and regarded it as a universal and major environmental carcinogen. However, although air pollution has been proposed as a holistic carcinogen, its damage to the human body may be the result of the simultaneous action of several major contaminants it contains.
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 μg/m3 for a long time, there is an increase in the risk of death. For every 10 μg/m3 increase in concentration, the total risk of death increased by 4%, the risk of death from cardiopulmonary disease increased by 6%, and the risk of death from lung cancer increased by 8%. In addition, PM2.5 is highly resistant to organic pollutants such as polycyclic aromatic hydrocarbons and heavy metals, which significantly increase the risk of carcinogenic, teratogenic and mutagenic.