Where does PM2.5 mainly come from?

The sources of PM2.5 can be divided into natural sources and man-made sources.

Natural sources include soil dust (containing oxide minerals and other components), sea salt (the second largest source of particulate matter, its composition is similar to that of seawater), plant pollen, spores, bacteria, etc. Disaster events in nature, such as volcanic eruptions that emit large amounts of volcanic ash into the atmosphere, forest fires or exposed coal fires, and dust storms will transport large amounts of fine particulate matter into the atmosphere.

Anthropogenic sources include fixed sources and mobile sources. Stationary sources include various fuel combustion sources, such as various industrial processes such as power generation, metallurgy, petroleum, chemistry, textile printing and dyeing, and smoke and catering fumes emitted from coal and gas or fuel oil during heating and cooking processes.

The flow source is mainly the exhaust gas emitted into the atmosphere when various types of vehicles use fuel during operation. Indoors, secondhand smoke is the main source of particulate matter. The source of particulate matter is incomplete combustion, so any tobacco product that relies on combustion will produce seriously harmful particulate matter. The same applies to burning gold paper, burning incense and burning mosquito coils.

Extended information:

PM2.5 is harmful to human health

Meteorological experts and medical experts believe that haze weather caused by fine particulate matter is harmful to human health. The harm is even greater than sandstorms. Particles with a particle size of 10 microns or more will be blocked from the human nose; particles with a particle size between 2.5 microns and 10 microns can enter the upper respiratory tract.

However, some of it can be excreted through sputum, etc., and it will also be blocked by the villi inside the nasal cavity, which poses relatively little harm to human health; while fine particles with a particle size of less than 2.5 microns have a diameter equivalent to that of a human being It is 1/20 the size of a hair and is not easily blocked. After being inhaled into the human body, it will directly enter the bronchus, interfere with the gas exchange in the lungs, and cause diseases including asthma, bronchitis, and cardiovascular disease.

Baidu Encyclopedia—PM2.5