EXHAUST GASES, professional harm — mix of the light-end products which are formed at fuel burning in internal combustion engines. The problem of pollution of the air basin of V. from the motor transport, airplanes and the nek-ry industrial enterprises is extremely urgent. Special researches showed that annually the huge amount of carbon compounds around the world is thrown out the environment. Fight for purity of free air became the major task not only specialists in the field of hygiene, but gained nation-wide and world value. In the USSR a number of government resolutions «About measures of pollution control of free air and about improvement of sanitary and hygienic conditions of the inhabited places» is adopted, «About nature protection and rational use of natural resources» and others, in to-rykh carrying out a number of complex actions for pollution control of air is provided.
V.'s structure of depends on a type of fuel, a duty, type and a condition of the motor, a season of year, time of day and other factors. Century of of the car contain on average carbon monoxide — 6,3%, carbon dioxides — 8,9%, oxygen — 2,3%, methane — 0,9%, hydrogen — 3%, nitrogen — 78,6%. In V. of diesel motors aldehydes and nitric oxides are found. At addition to fuel of an anti-detonator — tetraethyllead (see) in V. inorganic compounds of lead within 0,025 — 0,066 mg of m are found 3 . 3-,4-benzpyrene in number of 351 mkg/kg, hydrocarbon in number of 151 — 264 mkg/kg were found in the soot taken from exhaust pipes of airplanes (L. M. Shabad, G. A. Smirnov, 1969). The research of a top coat of the soil and vegetation around airfield showed existence of a significant amount of cancerogenic hydrocarbons, especially on runway platforms.
V.'s poisonings with can be observed at workers of garages, automobile repair shops, gas stations, at drivers and traffic controllers of transport more often. In garages, in the closed parkings during the operation of engines high concentration of carbon monoxide (see), capable to cause acute poisonings of the person can collect.
Till 40th years 20 century were considered that from all structure of V. of the greatest danger to the person is constituted by high concentration of carbon monoxide. By further researches it is established that V.'s danger of to the person is not limited to their own toxicity, and is complicated by the fact that new, even more toxic products — photooxidants can be formed of these gases as a result of the composite atmospheric photochemical reactions stimulated by ultra-violet radiation of the sun and other factors. To these biologically active products capable to damage vegetation to promote emergence of a number of diseases at the person, to reduce transparency of air, ozone, formaldehyde, peroxyacetyl nitrate, nitric oxides, acrolein, free radicals, organic peroxides belong. Pollution of free air oxidizers is for the first time noted in 1940 in Los Angeles when the population of the city began to show mass complaints to irritation of mucous membranes of eyes. It is established that the irritating effect was caused by hl. obr. formaldehyde, acrolein and peroxyacetyl nitrate. In addition to impact on an organ of sight, oxidizers even in very small concentration, especially at photochemical fogs, can complicate the course of respiratory diseases (bronchitis, bronchial asthma, emphysema of lungs and so forth). According to the American authors, in Los Angeles the maximum hour concentration of oxidizers made 0,63 mg/m 3 , and the maximum five-minute — 0,71 mg/m 3 . The highest concentration are noted, as a rule, at noon.
In the USSR the research of air on presence of oxidizers was conducted in various cities. According to V. A. Popov, the maximum total concentration of oxidizers in Moscow made 0,1 mg/m 3 , in Baku — 0,15 mg/m 3 , in Batumi — 0,04 mg/m 3 . The further researches conducted in Moscow showed that on highways with heavy traffic in sunny days the maximum one-time concentration of oxidizers in air reached 0,166mg/m 3 (ozone — 0,003 mg/m 3 , nitrogen dioxides — 0,1 mg/m 3 ), and the content of these substances at the level of upper floors of twelve-floor houses significantly did not differ from noted at the height of 1,5 from the earth.
The toxic effect caused by photochemical fog is connected with action to a large extent ozone (see), the total amount of oxidizers making a considerable part. There is a dependence of concentration of oxidizers and ozone on a season of year, time of day, meteorological factors, contents in the atmosphere of initial products of photochemical reactions, hl. obr. hydrocarbons (see) and nitric oxides (see. Nitrogaza ). A number of scientists expresses opinion that inhalation of air with the increased content of ozone leads to decrease immunobiol. properties of an organism. Nek-ry components B. of are active allergens. The question of existence in V. of of carcinogenic substances, in particular hydrocarbons (3-,4-benzpyrenes) in recent years was of particular importance. L. M. Shabad and sotr. migration of cancerogenic hydrocarbons in air, water, the soil is studied; ability of their deposition in lungs and dependence of cancerogenic effect from fiziol, conditions of an organism, a dose of influence and other factors is shown. The Soviet scientists saved up material, to-ry can be used for a gigabyte. rationing of contents in the environment of nek-ry carcinogenic substances (see. Oncogenous substances ).
Decrease in air pollution of V. of can be reached by improvement of engines. The main measures of fight against an adverse effect of V. of shall be carried out in the following directions: improvement of a design and working process of the existing types of engines, improvement of fuel quality and additives, creation of converters, filters, timely repair of motors, the correct adjustment of the carburetor, seal of flange connections, cracks for the purpose of prevention of hit of V. of in cabins of cars, etc. For the purpose of prevention of poisonings of V. of systematic medical control of the state of health of the persons which are affected by V. is carried out; a research of air on the content of oxidizers and separate components B. of. Control of work of positive-pressure ventilation and natural airing of rooms is exercised. Decrease in pollution of free air B. of is promoted by some other actions: underground tunnels, gas-purifying devices, creation of district highways, a rational design of an arrangement of the plants, enterprises, roads, sanitary protection zones with the obligatory accounting of a wind rose.
See also Sanitary protection of free air .
Bibliography: Feldman Yu. G. Hygienic assessment of motor transport as polluter of free air, M., 1975, bibliogr.; Feldman Yu. G. and Kurnosov V. N. Air pollution of the large cities photooxidants and their action on an organism, the Gigabyte. and dignity., No. 4, page 84, 1969; Shabad L. M. and Smirnov G. A. Soderzhaniye are 3,4 benzpyrenes in soot and exhaust gases of gas turbine and piston aviation engines, in the same place, No. 2, page 98, 1969; And 1 t s h u 1 1 e of And. P. Reactivity of organic substances in atmospheric photooxidation reactions, Publ. Hlth Serv. Pubi., No. 999-AP-26, p. 14, 1965; Fairchild E. J. Tolerance mechanisms, determinants of lung responces to injurions agents, Arch, environm. Hlth, v. 14, p. Ill, 1967; Smith L. E. Peroxyacetyl nitrate inhalation, ibid., v. 10, p. 161, 1965, bibliogr.
M. P. Trojan.