air pollution Sources
Products of burning of fuel in escalating quantities are thrown out in atmosphere as a result of use of coal, oil, gas for heating of inhabited, public and industrial buildings. At full combustion of fuel in atmosphere arrives С0 2 and water steams, at incomplete firm parts, soot, oxides of sulphur, carbon, nitrogen.
At burning of firm fuel, for example coal, flying ashes which on 55-77% consist of the smallest firm parts in the size to 5 microns are formed. The quantity of the ashes which are thrown out with smoke gases, depends from zolnosti fuel - percent of mineral impurity in all weight of fuel, i.e. Percent of the ballast which is not participating in process of burning. Zolnost coals it is various. For example, zolnost Donetsk anthracite makes 4,5%, and brown coal situated near Moscow - 40% the smallest zolnost have fire wood - 1%, and the greatest slates - about 50%. Hence, the more zolnost firm fuel, the more considerably ashes emission in atmosphere. Ashes include 42-49% oksida silicon (IV), 23-37% aljumosilikata, 9,8-16% of connections of iron, calcium, magnesium.
Except ashes at a smoke always there are the firm particles depending from nedozhoga of fuel and representing particles of not burnt down carbon. nedozhog depends on a design of the furnace and a burning mode. So, at burning of firm fuel on grid-iron lattices the basic part of ashes passes in a considerable quantity nedozhoga and soot. The smoke at this way of burning has dense black colouring. If coal preliminary to transform into a dust and to blow into a fire chamber through an atomizer together with a smoke in air it is thrown out more ashes, than nedozhoga.
As a part of ashes most of all contains oksida silicon (IV). Particles Si0 2 can deeply get into lungs and be the occurrence reason silikoza.
Soot in itself does not possess toxicity, but because of presence in it of resinous substances (3,4-benzpiren) gets properties of the carcinogen which long influence can promote increase in disease of the population a cancer of lungs. Among pollution of atmospheric air by products of burning of fuel the greatest value have oksidy sulfurs. So, at burning of coal and oil on each ton of fuel 40 and 30 kg oksidov sulfurs in pereuschete on oksid are formed accordingly are grey (IV), that speaks the high maintenance of sulphur in coal. Sulphur can be in fuel organic, sulphatic and sulphidic. At burning sulphatic sulphur passes in ashes, and sulphidic and organic burn down, forming oksid are grey (IV) (from 1 g sulfurs it is formed 2 g oksida sulfurs).
Oksid are grey (IV) (sulphurous anhydride) - colourless, with a specific unpleasant smell the gas amazing mainly bodies of breath. At inhalation of air polluted oksidom of sulphur, the food channel is amazed also, oxidation-reduction processes are broken, is oppressed fermentativnaja activity, decreases immunobiologicheskaja reactance of an organism and shifts from the higher nervous activity are observed. Maximum permissible daily average concentration oksida are grey (IV) in atmospheric air makes 0,05 mg/m 3 , and maksi-. ’: malno single - 0,5 mg/m 3 .
Oksid sulfurs - poison of green plantings, but are especially sensitive to it coniferous and fruit trees. This gas can cause also corrosion of metal coverings (roofs, monuments, etc.).
At fuel burning in atmosphere (II) (carbonic oxide) - a product of incomplete combustion (at burning 1 t fuel 20 kg oksida carbon are formed) is thrown out also much oksida carbon. This gas is extremely toxic. It has no colour and a smell, does not irritate a mucous membrane that strengthens danger of a poisoning with him. Possessing the raised affinity to blood haemoglobin, in 200 300 times exceeding affinity of haemoglobin to oxygen, oksid carbon connects it, forming karboksigemoglobin owing to what in fabrics oxygen starvation develops. From blood oksid carbon diffundiruet in a fabric, breaking in them activity of respiratory enzymes and, hence, fabric breath. Are especially sensitive to oxygen starvation of a cage of nervous system.
In easy cases of a poisoning the headache, weight in a head, weakness, dizziness, a nausea, vomiting, in heavier - loss of consciousness, a spasm is observed. Daily average maximum concentration limit oksida carbon (II) in atmospheric air makes 1 mg/m 3 , as much as possible single - 6 mg/m 3 .
At fuel burning in internal combustion engines (cars) in atmospheric air probably receipt of a considerable quantity oksida carbon.
Oksid carbon it is easier than air, therefore its considerable part is carried away in the top layers of air and prizemnyj the atmosphere layer becomes soiled a little. However sometimes near to the large industrial enterprises it is possible to find out oksid the carbon which concentration is equal 100-300 t/i 3 .
Transport. Now pollution of atmosphere of air by exhaust gases of motor transport gets the increasing value. Exhaust gases of motor vehicles contain in the structure oksidy carbon, nitrogen, hydrocarbons, lead connections, soot and the chemical substances which quantity makes now more than 200.
Depending on quality of fuel and its impurity in exhaust gases sulphur and lead connections can contain. The quantity of substances polluting atmospheric air depends on intensity of movement of motor transport, width of streets, their relief etc. Containing in exhaust gases oksidy nitrogen and hydrocarbons under the influence of ultra-violet radiation of the Sun can form new connections - photooxidizers. Thus At first the complex of oxidizers-organic of peroxides, aldehydes, ketonov, spirits, phenols, epoksidov, free radicals are formed ozonidy, then. All these connections accelerate oxidation oksidov nitrogen and conduct to increase in the maintenance of ozone, and also to occurrence of nitrates, nitrites and other connections.
The Industrial enterprises. Many industries are sources of pollution of atmospheric air. So, the enterprises black and nonferrous metallurgy pollute air a dust, oksidami carbon (II), nitrogen (II, IV), are grey (IV). Factories of the copper and svintsovo-zinc industry throw out lead, zinc, arsenic, mercury in air. The enterprises of the aluminium industry are an air pollution source fluoric connections, the enterprises of the chemical industry - steams and gases of various chemical substances from which many possess high toxicity.
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