smog


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Related to smog: photochemical smog, acid rain

smog

(smŏg) [smoke+fog], dense, visible air pollutionair pollution,
contamination of the air by noxious gases and minute particles of solid and liquid matter (particulates) in concentrations that endanger health. The major sources of air pollution are transportation engines, power and heat generation, industrial processes, and the
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. Smog is commonly of two types. The gray smog of older industrial cities like London and New York derives from the massive combustion of coal and fuel oil in or near the city, releasing tons of ashes, soot, and sulfur compounds into the air. The brown smog characteristic of Los Angeles and Denver in the late 20th cent. is caused by automobiles. Nitric oxide from automobile exhaust combines with oxygen in the air to form the brown gas nitrogen dioxide. Also, when hydrocarbons and nitrous oxides from auto emissions are exposed to sunlight, a photochemical reaction takes place that results in the formation of ozone and other irritating compounds. In some instances, atmospheric pollutants accumulate and become concentrated when air movement is stopped by a temperature inversiontemperature inversion,
condition in which the temperature of the atmosphere increases with altitude in contrast to the normal decrease with altitude. When temperature inversion occurs, cold air underlies warmer air at higher altitudes.
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: Usually the air is warmer at the earth's surface and colder above; in a temperature inversion a layer of warm air forms above and holds down a layer of cool air at the ground. Smog usually results in reduced visibility, irritation of the eyes and respiratory system, and damage to paint, metal, rubber, and other materials. Prolonged smogs (generally caused by temperature inversions) are often lethal to persons with respiratory ailments. As the result of an unremitting smog in 1948 in Donora, Pa., more than 5,000 persons were reported ill and the deaths of 20 persons were recorded. In London, smog accounted for the deaths of more than 4,000 persons in 1952 and 106 persons in 1962.

Smog

 

the severe air pollution over large cities and industrial centers. There are two types of smog. One is a thick fog that contains smoke or gaseous industrial wastes as, for example, in London; the other is a pall of corrosive gases and aerosols in high concentrations (without fog). The latter type arises under the effect of ultraviolet solar radiation in the atmosphere as a result of photochemical reactions occurring in the exhausts of motor vehicles and the gaseous wastes of chemical plants as, for example, in Los Angeles. Smog is usually observed when there is low atmospheric turbulence and, consequently, an even distribution of air temperature with height, especially in temperature inversions during a calm or a slight wind.

Smog, which reduces visibility and accelerates the corrosion of metals and man-made structures, is also harmful to human health. Intense and prolonged smog can be a cause of increased morbidity and mortality.

smog

[smäg]
(meteorology)
Air pollution consisting of smoke and fog.

smog

A condition in which the surface visibility is reduced because of smoke particles suspended in the moist air.

smog

a mixture of smoke, fog, and chemical fumes
References in periodicals archive ?
Health experts recommend artificial tears for eyes as one way of dealing with smog.
People may experience short-term skin and respiratory conditions such as eye irritation, coughing, throat/chest irritation and skin irritation as a result of smog.
Smog is a mixture of dust, ozone, industrial emissions, carbon monoxide and nitrogen oxide, and when it mixes with moisture during the night and heated by the high voltage, it results in breakage of insulators.
In past few years the phenomenon of smog has grown worse because of increasingly high polluted environment secondary to the establishment of large number of factories, heavy traffic, extraordinary construction work and unchecked cutting of trees due to urbanization.
Addressing air quality issues only when there are serious smog problems is not a winning strategy," said Perotti, adding "governments must systematically adapt regulations to limit activities that pollute the air.
Mercado said the smog and the haze could dissipate during rainfall because the smog comprises small particles that could be dissolved by rains.
A basic component of smog, ozone can irritate air passages, reduce lung function, aggravate asthma, and inflame and damage the cells lining the lungs, the U.
In December 1952, a thick smog settled over London, resulting in unprecedented morbidity and mortality, bringing the relationship between air pollution and health to the attention of the general public, the government, the media, and the scientific community.
Some complained about month-long waits to get mandatory retests of cars that had been deemed "gross polluters" by previous smog tests.
Smog, after all, is little more than a minor irritant.
These include: a camera lens, smog, marble, a wasp's nest, soil, a mirror, satin, hair, incense, embroidery, sand, bits of maps, and clockworks.
Asher's paper, together with other investigations of smog effects at lower elevations in the Los Angeles basin, prompted the Forest Service to look into the matter seriously.