The air quality requirements are different for different ranges. Open areas should maintain the natural quality of the air. Urban air should have a higher quality. The local air pollution sources, especially the air quality requirements inside the workshop may be lower, but should not endanger the health of staff or residents. China promulgated the "Atmospheric Environmental Quality Standards" and "Industrial Enterprises Design Health Standards" and other regulations in order to control air pollution. Air pollution is localized, such as indoor pollution, individual chimney pollution; regional, such as urban traffic pollution. Due to the flow of air, localized pollution can become regional and even become global after the expansion of regional pollution.

Air pollution can result in increased dustfall, reduced visibility, poor tree growth, and even wilting. However, the most important hazard is the impact on human health, ranging from illness and death to death. The 1952 London smog caused by atmospheric sulfur pollution killed 4,000. Acid rain caused by atmospheric pollution, plant damage, corrosion of buildings, victims of a wider area, is causing serious concern.

Sources of atmospheric pollution are mainly the combustion of fossil fuels (coal, oil, gas). Pollutants emitted by some industrial processes also pollute the atmosphere, but generally only affect nearby areas. Gale and vehicles cause dust and sometimes air pollution (see Traffic Engineering). Volcanic eruptions are another source of pollution.

Air pollutants are: ① dust. Collectively, all non-gaseous pollutants, also known as particulate matter, mainly dust and smoke. Dust generally comes from topsoil. Smoke is a product of incomplete combustion, the main body is carbon particles, adsorption of other impurities. The hazards of soot are the reduction of the general quality and visibility of the atmosphere. However, the lead particles formed during the combustion of leaded petrol and dust and smoke from industrial processes can be directly pathogenic. ② carbon monoxide. Incomplete fuel combustion products, is colorless, odorless, toxic gas, slightly lighter than air, diffuse faster. In cities with heavy traffic, carbon monoxide in the surface air comes from cars at concentrations of up to 10-100ppm, while living in air at 10ppm for 8 hours may affect people's mental activity. ③ sulfur dioxide. Sulfur fossil fuel combustion products. In China mainly from coal-fired boilers and stoves. Corrosion artifacts to stimulate the respiratory tract. Chimney to high altitude diffusion, often oxidation of sulfur trioxide, the formation of sulfuric acid or sulfate, into the raindrops, there will be pH below 5 acid rain. ④ nitrogen oxides. Nitrogen oxides such as nitric oxide and nitrogen dioxide are the products of fuel combustion at high temperatures. Nitrogen in the atmosphere is oxidized to nitric oxide at high temperatures, which in turn is converted to nitrogen dioxide. Nitrogen oxides are reactants in atmospheric photochemical reactions that directly affect health at high concentrations. ⑤ hydrocarbons. Gas is generally incomplete combustion of the product. Lower concentrations are not directly hazardous to health, but are reactants in atmospheric photochemical reactions. ⑥ photochemical reaction oxidant. The reaction products of nitrogen oxides and hydrocarbons under sunlight, ozone, nitric oxide, nitrogen dioxide, a mixture of peroxyacetyl nitrate (PAN), formaldehyde, acrolein, nitric acid and the like are secondary con***inants . Their pollution parameters are total oxidants. The photochemical reaction with the oxidant fumes called photochemical smog, has caused serious harm, the comprehensive impact on health is still under study. Concentrations of about 0.1 ppm irritate the mask and respiratory tract. In addition, nitric acid may be another factor causing acid rain. ⑦ carbon dioxide. Under normal conditions, the atmospheric carbon dioxide is generally in equilibrium due to photosynthesis and respiration of the plants. However, the increasing amount of fossil fuel burned increases the concentration of carbon dioxide in the atmosphere. Because of the greenhouse effect of carbon dioxide, some people think that it is possible to cause an increase in the average temperature of the earth's atmosphere, melting polar ice and causing serious environmental problems.

Air pollution control measures, afforestation and urban greening contribute to the improvement of air quality, and the creation of windbreaks can prevent the spread of dust. However, prevention and treatment of air pollution mainly lies in: ① energy innovation. When possible, use uncon***inated energy sources (solar, wind, geothermal energy, electricity and steam), or low-pollution sources of energy (gas and oil) to replace coal. The distribution of coal should also take into account pollution control, low-sulfur coal should be allocated to the stove and small combustion equipment, the more easy to adopt pollution prevention measures of large-scale combustion equipment should be allocated high sulfur coal. High sulfur fuel available desulfurization technology to reduce sulfur content. Gas desulfurization technology see city gas purification. ② equipment and operation of innovation. Innovative dust removal equipment will help to reduce the amount of soot, improve the efficiency of combustion equipment can reduce the pollution of carbon monoxide and hydrocarbons. Flame temperature control, can reduce nitrogen oxidation and carbon dioxide decomposition. The prevention and control of automobile exhaust pollution mainly relies on the reforming of the combustion system of automobiles. A great deal of research has been carried out and the reform is still under way. Lead in the car exhaust gas only need to add lead gasoline to eliminate. ③ exhaust gas treatment. Is the means of prevention and control of air pollution. Smoke in the flue gas can be filtered, washed, centrifuged, electrostatic precipitation, sonic deposition and other methods and air separation. Removal of sulfur dioxide in flue gas there are a variety of ways: the limestone powder blowing into the combustion chamber, and sulfur dioxide synthesis of ash; with alkaline substances absorb or absorb sulfur dioxide, and then use; in the role of catalyst combustion flue gas, so that sulfur dioxide into tris Sulfur dioxide, flue gas cooling condensate combined with sulfuric acid. Nitrogen oxides in flue gases can also be chemically removed.