1. AIR POLLUTION

2. any adverse change in the composition of Earth's atmosphere as a consequence of it different gases, water vapor and particulate matter (due to natural processes or human activities). Approximately 10% of pollutants released into the atmosphere as a result of natural processes such as volcanic eruptions, accompanied by emission of ash into the atmosphere, scattered acids, including sulfuric acid, and a variety of toxic gases.

3. In addition, the main sources of sulfur in the atmosphere are sea spray and decaying plant residues. Also of note is forest fires, which resulted in the formation of dense clouds of smoke enveloping large areas, and dust storms. Trees and bushes produce a lot of volatile organic compounds (VOC), which form a blue haze that covers most of the Blue Ridge Mountains in the United States (in terms of "Blue Ridge").

4. Microorganisms present in the air (pollen, fungi, bacteria, viruses) cause many people become allergic and infectious diseases. The remaining 90% of pollutants are of anthropogenic origin. Major sources are the combustion of fossil fuels in power plants (of smoke) and car engines, industrial processes, non-combustion, but resulting in a dusty atmosphere, for example through erosion of soil, surface mining, blasting and leaks of VOCs through valves, pipe joints in refineries and chemical plants, and from the reactors, storage of solid waste and a variety of mixed sources.

6. Contaminants entering the atmosphere, transported long distances from the source, and then returned to the earth's surface in the form of solid particles, droplets, or chemical compounds dissolved in precipitation. Chemical compounds, the source of which is on the ground level, quickly mixed with the air of the lower atmosphere (troposphere).

7. They are called primary pollutants. Some of them, enter into chemical reactions with other pollutants, or with the main components of air (oxygen, nitrogen and water vapor) to form secondary pollutants. As a result, there are phenomena such as photochemical smog, acid rain and ozone formation in the surface layer of the atmosphere. The source of energy for these reactions is solar radiation.

8. Secondary pollutants - contained in the atmosphere, photochemical oxidants and acids - are a major threat to human health and global environmental change.