Answer the question: carbon monoxide, carbon dioxide, nitrogen oxides, sulfur dioxide, inhalable particulate matter, that is, dust. Now there are PCBs and polycyclic aromatic hydrocarbons in Pm2.5.

Air pollution sources are the sources of air pollutants, which mainly include the following three types:

(1) Industry: Industry is an important source of air pollution. There are many kinds of pollutants discharged into the atmosphere by industry, and their properties are complex, including soot, sulfur oxides, nitrogen oxides, organic compounds, halides, carbon compounds and so on. Some of them are smoke and some are gas.

(2) domestic stoves and heating boilers: a large number of domestic stoves and heating boilers in cities need to consume a lot of coal, and coal will release a lot of harmful substances such as dust, sulfur dioxide and carbon monoxide to pollute the atmosphere during combustion.

(3) Transportation: Cars, trains, planes and ships are the main means of transportation at present, and the exhaust gas generated by burning coal or oil is also an important pollutant. Especially, cars in cities are large and concentrated, and the pollutants discharged can directly attack people's respiratory organs, causing serious air pollution in cities and becoming one of the main air pollution sources in big cities. The exhaust gas emitted by automobiles mainly includes carbon monoxide, sulfur dioxide, nitrogen oxides and hydrocarbons, and the first three substances are very harmful.

3. Hazards of air pollution

Hazards of air pollution mainly include the following aspects:

(1) Hazards to human health: people need to breathe air to maintain their lives. An adult breathes about 21,111 times a day, and inhales 1.5 ~ 21 cubic meters of air. Therefore, polluted air has a direct impact on human health.

The harm of air pollutants to human body is various, mainly manifested in respiratory diseases and physiological dysfunction, and mucosal tissues such as eyes and nose are stimulated to get sick.

when the concentration of pollutants in the air is very high, it will cause acute pollution poisoning, or worsen the symptoms, and even kill thousands of people in a few days. In fact, even if the concentration of pollutants in the atmosphere is not high, breathing this polluted air for years will cause diseases such as chronic bronchitis, bronchial asthma, emphysema and lung cancer.

(2) Harm to plants: Air pollutants, especially sulfur dioxide and fluoride, are very harmful to plants. When the concentration of pollutants is very high, it will cause acute harm to plants, causing damage to the surface of plant leaves, or directly causing leaves to wither and fall off; When the concentration of pollutants is not high, it will cause chronic harm to plants, make the leaves of plants fade green, or there are no harmful symptoms on the surface, but the physiological functions of plants have been affected, resulting in the decline of plant yield and deterioration of quality.

(3) Impact on weather and climate: The impact of atmospheric pollutants on weather and climate is very significant, which can be explained from the following aspects:

① Reduce the amount of solar radiation reaching the ground: A large number of soot particles discharged into the atmosphere from factories, power stations, automobiles and household heating equipment make the air very turbid, which blocks the sunlight and reduces the amount of solar radiation reaching the ground. According to observation and statistics, in the days when the smoke is not scattered in large industrial cities, the amount of direct sunlight hitting the ground is reduced by nearly 41% compared with the days without smoke. In cities with serious air pollution, it will lead to poor growth and development of people, animals and plants due to lack of sunlight every day.

② increasing atmospheric precipitation: many particles discharged from large industrial cities have the function of condensation nuclei of water vapor. Therefore, when there are other precipitation conditions in the atmosphere, there will be precipitation weather. In the downwind areas of big industrial cities, there is more precipitation. American imported Puweixin Cat ③ Acid rain: Sometimes, the rain falling from the sky contains sulfuric acid. This kind of acid rain is formed by the oxidation of sulfur dioxide, a pollutant in the atmosphere, to form sulfuric acid, which falls with the precipitation in nature. Sulfuric acid rain can destroy large areas of forests and crops, corrode and break paper products, textiles and leather products, deteriorate metal antirust coatings and reduce their protection, and also corrode and pollute buildings.

④ increase the atmospheric temperature: over the big industrial cities, the temperature of the air near the ground is higher than that in the surrounding suburbs because a large amount of waste heat is discharged into the air. This phenomenon is called "heat island effect" in meteorology.