Under pollution refers to the process of bringing in the air, or the education of physical agents, chemical substances or organisms, adversely affecting the living environment or damage property. In a sense, pollution can be considered and air removal from individual gas components (in particular, oxygen) major technological objects. And it's not just that fit into the atmosphere of gases, dust, sulfur, lead and other substances harmful to the human body, they adversely affect the cycles of many of the features on Earth. Polluting and toxic substances are transported over long distances, with precipitation falls into the soil, surface water and groundwater, in the oceans, poisoning the environment, have a negative impact on obtaining plant mass.
Air pollution affects the climate of the planet. In this regard, there are three points of view. 1. in this century global warming due to increasing concentrations of Sog in the atmosphere, and by the middle of the next century there will be a catastrophic global warming, accompanied by a strong increase in the level of the oceans. 2. air pollution reduces the level of solar radiation increases the number of cloud condensation nuclei, as a result of the Earth's surface cools, which in turn can cause a new glaciation in the northern and southern latitudes (supporters of this point of view a little bit). 3. According to the proponents of a third point of view, both the uravnovesatsa and the Earth's climate will remain unchanged.
The main sources of air pollution, fuel and energy, complex enterprise, manufacturing and transportation. More than 80% of all releases to air are emissions of oxides of carbon, sulphur dioxide, nitrogen, hydrocarbons, solids. Of the gaseous pollutants in the largest quantities of carbon oxides are emitted, carbon dioxide, carbon monoxide, formed primarily by the combustion of the fuel. In large quantities into the atmosphere are emitted and oxides of sulphur: sulphur dioxide, sulphur dioxide, carbon disulfide, hydrogen sulfide, etc. The most numerous class of air pollutants in major cities are hydrocarbons. Regular gas ingredients of air pollution are also free chlorine, compounds, etc.
In addition to the gaseous pollutants in the atmosphere are tens of millions of tons of particulate matter. This dust, soot, carbon black, which in the form of small particles to penetrate the Airways and settle in the bronchi and lungs. But that's not all — "on the way" they are enriched by sulphates, lead, arsenic, selenium, cadmium, zinc and other elements and compounds, many of which are carcinogenic. From this point of view is especially dangerous to human health the asbestos dust. To the first class of danger also owns mercury, arsenic, cadmium and vanadium. (Curious results of comparative analysis, performed by American scientists. the lead content in bones of the skeleton's Peru, lived 1600 years ago, 1000 times less than in the bones of modern citizens of the United States.)
Air pollution is associated with a specific phenomenon of acid rain.
Earth's atmosphere is relatively well ignores short-wave solar radiation, which is almost completely absorbed by the Earth's surface. Warming by absorbing solar radiation, the surface becomes a source of mostly long-wave radiation, part of which goes into outer space.
Ucenyeissledovateli continue to argue about the so-called greenhouse gases (58). Of greatest interest is the impact of increasing concentrations of carbon dioxide (GES), the atmospheric greenhouse effect. It has been suggested that the famous scheme: "growing concentration of carbon dioxide increases the greenhouse effect, leading to a warming of the global climate" — is extremely simplified and very far from reality, as the most important "greenhouse gas" is not carbon dioxide (not nitrous oxide, not methane or hydrochlorofluorocarbons) and water vapor. With reservations, that the concentration of water vapor in the atmosphere is determined only by the climate system is not credible, as the human impact on the global water cycle is conclusively proven.
As a scientific hypothesis will point to the following consequences of the greenhouse effect. First, according to the most common estimates, by the end of the 21st century the atmospheric content of Sog would double, which inevitably will result in an increase in the average global surface temperature in 3-5° c. The warming is expected to be stronger in the high latitudes and accordingly will become more arid summer in temperate latitudes in the northern hemisphere.
Secondly, it is expected that the increase in global mean surface temperature would lead to a sea level rise of 20-165 cm due to the thermal expansion of water. (The ice sheet of Antarctica, its destruction is not inevitable because melting requires higher temperatures. in any event, the melting of the Antarctic ice cap would take a very long time.)
Vtret?ih, atmospheric concentration of Sog can have a very beneficial impact on crop yields. Experiments suggest that the progressive growth of Sog in the air natural and cultural vegetation reached an optimal state of surface of sheet plants will increase: increase proportion of dry matter of leaf, increase the average size of fruit and seed number, will accelerate the ripening of crops, and their yields will rise.
Vcetvertyh, in the high latitudes of the natural forests, boreal particularly can be highly sensitive to temperature changes. Warming could lead to a drastic reduction of the boreal forests, and the movement of their borders to the North. The forest of tropics and subtropics are probably more sensitive to changes in precipitation, rather than temperature. However, projections of future changes in precipitation is very uncertain.
In General, atmospheric greenhouse effect is an equation with many unknowns. Most scientists believed that the warming is real will. Indeed, many argue that global warming (about 1° c in the 20th century) has already happened (at least its first stage), but it was kind of a masked by natural climate change. However, there are scientists who believe that, paradoxically, the accelerating accumulation of Sog can lead to warming and cooling. This opinion is based on the fact that the forecast "overheating" of the Earth by doubling the concentration of Sog in the air is made on the basis of an erroneous assessment of the greenhouse effect of the gas. Is that the proponents of "overheating" do not take into account the enormous role of ocean waters in the absorption of anthropogenic Sog and underestimate the value of terrestrial biota, and soil, therefore, as a powerful assimilatorov "excess" of atmospheric carbon dioxide.