The atmosphere protects the Earth from sudden temperature fluctuations — in the absence of atmosphere and water surface temperature of the Earth during the day would fluctuate in the range 200сС. Due to the presence of oxygen in the atmosphere participates in the exchange and circulation of substances in the biosphere. In the present state of the atmosphere exists hundreds of millions of years, all life adapted to a strictly defined composition. Envelope of gas protects living organisms from harmful ultraviolet, x-rays and cosmic rays. The atmosphere protects Earth from falling meteorites. Distributed in the atmosphere and scatter sunlight, creating a uniform illumination; it is the medium where the sound is spread. Because of the action of gravitational forces, the atmosphere has not dissipated in space, and surrounds the Earth rotates along with it.
The main (mass) component of the air — nitrogen in the lower layers of the atmosphere, its content is 78,09%. Gaseous nitrogen is inert, and the compounds in the form of nitrate, it plays an important role in biological metabolism.
The most active in the biosphere processes gas atmosphere — oxygen. Its content in the atmosphere is about 20,94%. Animals absorb oxygen during respiration and produce plants as a normal product of photosynthesis.
An important part of the atmosphere — carbon dioxide (CO2), constituting 0.03 percent of its volume and significantly affect weather and climate on Earth. Dioxide content in the atmosphere is not constant, it enters the atmosphere from volcanoes, hot springs, in the breath of humans and animals during forest fires, consumed by plants, is highly soluble in water.
In small quantities in the atmosphere contain carbon monoxide (co), inert gases (argon, helium, neon, krypton, xenon). Of them, most of the argon 0,934%. In the composition of the atmosphere also comprises hydrogen and methane. Inert gases released to the atmosphere in the continuous process of natural radioactive decay of uranium, thorium, and radon.
In addition to gases in the atmosphere are water and aerosols. In the atmosphere water is in solid (ice, snow), liquid (droplet) and gaseous (vapor) state. The condensation of vapour formed clouds. Complete upgrade of water vapor in the atmosphere occurs within 9-10 days. The primary source of atmospheric heat energy for Earth is the Sun. The surface of the Earth reaches only a small fraction of the radiant energy of the Sun; part of the energy reaching the surface is reflected, and the rest is absorbed, turning into heat and causing convective motion in the atmosphere. 71% of the Earth's surface occupied by water, so the absorption of solar energy accompanied by evaporation.
With the development of industrial activity for an increasing share of pollution accounted for the anthropogenic pollution, which are divided into local and global. A local associated with cities and industrial regions; global pollution impact on biosphere processes in General on Earth. Air that is in constant motion, harmful substances are transferred to the hundreds of thousands of miles, into the soil, bodies of water, and then re-enter the atmosphere. Air pollutants are divided into mechanical, physical and biological.
Mechanical dust, phosphates, lead, mercury generated by burning fossil fuels during the production process.
Physical pollutants include:
thermal (receipt in the atmosphere of hot gases);
light (the deterioration of the natural lighting of the area under the influence of artificial light sources);
noise (as a consequence of anthropogenic noise);
electromagnetic (from power lines, radio and television, operation of industrial installations);
radioactive, associated with higher levels of intake of radioactive substances into the atmosphere.
Biological pollutants are mostly the result of the multiplication of micro-organisms and anthropogenic activities (power, industry, transport, armed forces).
Environmentalists warn that if we fail to reduce emissions of carbon dioxide into the atmosphere, then our planet will have a catastrophe associated with an increase in temperature due to the so-called greenhouse effect. The essence of this phenomenon lies in the fact that the atmosphere with increased CO2 and methane CH4 fairly freely passes ultraviolet radiation from the sun and at the same time, the delay reflected from the surface of the infrared rays, which leads to temperature rise and therefore to climate change.
Polluting substances enter the human body through the respiratory system. The daily amount of air inhaled for one man is 6 - 12 m3. During normal breathing with each breath enters the body from 0.5 to 2 l of air. Inhaled air through the trachea and bronchi enters the lung alveoli, where gas exchange occurs between the blood and the lymph. Depending on the size and properties of pollutants, their absorption is different. Coarse particles trapped in the upper respiratory system, which means and, if they are not toxic, can cause a condition called bronchitis of field. Dust particles can lead to profes-sional disease, which is generally called pneumoconiosis. A person can live without food for 30 to 45 days, without water for 5 days, and without air for only 5 min. the Harmful effects of a variety of dust and industrial emissions per person are determined by the amount of pollutants entering the body, their condition, composition and time of exposure. Atmospheric pollution may have on human health small effect, and can lead to complete intoxication.
The devastating effects of industrial pollution depends on the type of substance. Chlorine causes damage to the organs of sight and respiration. Fluoride entering the body to leach calcium from the bones and reduce its content in blood; inhalation of fluorides adversely affects the respiratory tract. Hydrosulfide affects the cornea of the eyes and respiratory system, causes headaches; at high concentrations may be fatal. Carbon disulfide is a poison of the nervous action and may cause mental disorder; the acute form of poisoning leads to drug loss of consciousness. Dangerous to inhale vapours or toxic heavy metal compounds, beryllium compounds. Sulfur dioxide affects the respiratory tract, carbon monoxide inhibits the transport of oxygen, making the oxygen; prolonged inhalation of carbon monoxide can be fatal to humans.
Dangerous in low concentrations in the atmosphere, aldehydes and ketones. Aldehydes are irritating effect on the organs of sight and smell, are drugs that destroy the nervous system; the nervous system impress also phenolic compounds and organic sulphides. Pollution harmful impact on plants. Gases have different effects on plants, and the susceptibility of plants to the same gases varies; the most harmful sulfur dioxide, hydrogen fluoride, ozone, chlorine, nitrogen dioxide, hydrochloric acid. Contaminants from the atmosphere this substances have a negative impact on agricultural crops as due to the direct toxicity of green mass, and due to the intoxication of the soil.
Atmospheric pollution by industrial emissions significantly enhances the effect of corrosion. Acid gases contribute to corrosion of steel structures and materials; sulfur dioxide, nitrogen oxides, hydrochloride when combined with water to form acids, enhancing chemical and electrochemical corrosion, destroy organic materials (rubber, plastics, dyes). On a steel structure negatively influence the ozone and chlorine. Even a small content of nitrates in the atmosphere causes corrosion of copper and brass. A similar effect and acid rain: to reduce soil fertility, adversely affect flora and fauna, reduce the service life of electrochemical coatings, particularly chromium-Nickel paints, reduces the reliability of machines and mechanisms, under the threat there are more than 100 thousand of used types of colored glass.
Climate change affects agriculture. Warming increases the length of the growing season (10 days at the temperature on the GS). Increasing the concentration of carbon dioxide leads to increased productivity.
Anthropogenic processes include the destruction of the ozone screen, which is called:
work refrigerators on the aerosol and freon installations;
the selection of NO2 as a result of decomposition of mineral fertilizers;
flights at high altitude and launches of carrier rockets satellites (the emission of nitrogen oxides and water vapor);
nuclear explosions (formation of nitrogen oxides);
the processes that contribute to the penetration into the stratosphere of chlorine compounds of anthropogenic origin, as well as metalcore-form, carbon tetrachloride, methyl chloride.
Scientists estimate that currently, ozone is reduced annually by about 0.1%. This can greatly change the climate and cause other negative consequences.
The development of technology is accompanied by an increase in the number and power of sources of ionizing radiation, which includes nuclear power plants, enterprises producing and processing nuclear fuel, waste storage, research institutes, testing grounds. The development of nuclear energy is accompanied by the growth of radioactive waste, the image-requesting at production and reprocessing of nuclear fuel. The activity of this waste is growing every year, and in the near future will be a serious danger to the environment.