Industrial and economic development is usually accompanied by an increase in environmental pollution. Most large cities are characterized by a significant concentration of industrial facilities in relatively small areas, which poses a risk to human he alth.
One of the environmental factors that have the most pronounced impact on human he alth is air quality. Emissions of pollutants into the atmosphere present a particular danger. This is due to the fact that toxicants enter the human body mainly through the respiratory tract.
Air emissions: sources
Distinguish between natural and anthropogenic sources of pollutants in the air. The main impurities that contain atmospheric emissions from natural sources are dust of cosmic, volcanic and vegetable origin, gases and smoke generated as a result of forest and steppe fires, products of destruction and weathering of rocks and soils, etc.
Pollution levelsair environment natural sources are background. They change little over time. The main sources of pollutants entering the air basin at the present stage are anthropogenic, namely, industry (various industries), agriculture and transport.
Emissions of enterprises into the atmosphere
The largest "suppliers" of various pollutants to the air basin are metallurgical and energy enterprises, chemical production, construction industry, mechanical engineering.
In the process of burning fuels of various types by energy complexes, large amounts of sulfur dioxide, carbon and nitrogen oxides, and soot are released into the atmosphere. A number of other substances are also present in emissions (in smaller quantities), in particular hydrocarbons.
The main sources of dust and gas emissions in metallurgical production are melting furnaces, pouring plants, pickling departments, sintering machines, crushing and grinding equipment, unloading and loading of materials, etc. The largest share among the total amount of substances entering the atmosphere is carbon monoxide, dust, sulfur dioxide, nitric oxide. Manganese, arsenic, lead, phosphorus, mercury vapours, etc. are emitted in somewhat smaller quantities. Also, in the process of steelmaking, emissions into the atmosphere contain vapor-gas mixtures. They contain phenol, benzene, formaldehyde, ammonia and a number of other hazardous substances.
Harmful emissions into the atmosphere from chemical enterprisesindustries, despite their small volumes, pose a particular danger to the natural environment and humans, since they are characterized by high toxicity, concentration and considerable diversity. Mixtures entering the air, depending on the type of product, may contain sulfur oxides, volatile organic compounds, fluorine compounds, nitrous gases, solids, chloride compounds, hydrogen sulfide, etc.
In the production of building materials and cement, emissions into the atmosphere contain significant amounts of various dusts. The main technological processes leading to their formation are grinding, processing of batches, semi-finished products and products in hot gas flows, etc. Contamination zones with a radius of up to 2000 m can form around plants that produce various building materials. They are characterized by a high concentration of dust in the air containing particles of gypsum, cement, quartz, and a number of other pollutants.
Vehicle emissions
In large cities, a huge amount of pollutants in the atmosphere comes from motor vehicles. According to various estimates, they account for 80 to 95%. Exhaust gases consist of a large number of toxic compounds, in particular nitrogen and carbon oxides, aldehydes, hydrocarbons, etc. (about 200 compounds in total).
Emissions are highest at traffic lights and intersections, where vehicles travel at low speed and at idle. Calculation of emissions inatmosphere shows that the main components of the exhaust in this case are carbon monoxide and hydrocarbons.
It should be noted that, unlike stationary sources of emissions, the operation of vehicles leads to air pollution on city streets at the height of human growth. As a result, pedestrians, roadside residents, and vegetation growing in the surrounding areas are exposed to the harmful effects of pollutants.
Agriculture
Emissions of harmful substances into the atmosphere in rural areas are mainly the result of the activities of livestock complexes and poultry farms. From the premises in which poultry and livestock are kept, hydrogen sulfide, ammonia and some other gases are released into the air, spreading over considerable distances. Also, hazardous toxicants enter the air as a result of the activities of crop farms when spraying pesticides and fertilizers on the fields, dressing seeds in warehouses, etc.
Other sources
In addition to the above sources, emissions of pollutants into the atmosphere are produced by oil and gas refineries. It also occurs as a result of the extraction of mineral raw materials and its processing, the release of gases and dust from underground mine workings, the burning of rocks in dumps, the operation of waste incineration plants, etc.
Influence on a person
According to various sources, there is a direct link betweenair pollution and a number of diseases. For example, the duration of the course of respiratory diseases in children who live in relatively polluted areas is 2-2.5 times longer than in those living in other areas.
In addition, in cities characterized by unfavorable environmental conditions, children have functional deviations in the system of immunity and blood formation, violations of compensatory-adaptive mechanisms to environmental conditions. Many studies have also found a link between air pollution and human mortality.
The main components of air emissions from various sources are suspended solids, oxides of nitrogen, carbon and sulfur. It was revealed that the zones with excess MPC for NO2 and CO cover up to 90% of the urban area. These macro-components of emissions can cause serious diseases. The accumulation of these contaminants leads to damage to the mucous membranes of the upper respiratory tract, the development of pulmonary diseases. In addition, elevated concentrations of SO2 can cause dystrophic changes in the kidneys, liver and heart, and NO2 - toxicosis, congenital anomalies, heart failure, nervous disorders, etc. Some studies have found a relationship between the incidence of lung cancer and the concentrations of SO2 and NO2 in the air.
Conclusions
Pollution of the environment and, in particular, the atmosphere,has adverse effects on the he alth of not only the present, but also future generations. Therefore, we can safely say that the development of measures aimed at reducing emissions of harmful substances into the atmosphere is one of the most urgent problems of mankind today.
