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 ?
Additionally, The Golden Smog is this year to be the finishing point for The pALEgrimage, an event supporting The Great North Air Ambulance.
e pollution warning was expected to be lifte d by this afternoon and Salendine Nook weatherman Smog on | Yesterday the Department for Environment, Food and Rural Aairs (Defra), described the air quality index as four out of 10 in the Colne Valley and Meltham areas, increasing to index ve for Deighton, Paddock, Birchenclie, Honley, Hudderseld, and Brighouse.
Construction works too are major contributors for the smog in this season as they lead to more pollution in the air," Yadav said.
Lead researcher Shakir Franco Suglia reported that smog particles could be reaching, and impacting, the brain.
But mandating smog tests still won't solve the problem.
The US model is far from perfect, but its basic features arguably provide a clearer path toward smog reduction than the Canadian approach.
According to NCPA, NRDC used smog-forming emission levels from the mid-1990s to predict smog levels in the 2050s and 2080s.
In an earlier study (Bell and Davis 2001), we analyzed the relationship between pollution and mortality and morbidity for the London smog of 1952.
In fact, emissions of nitrogen oxide -- the main cause of smog -- increased during that period.
And yet, like Frank Stella's early '60s series of notch paintings, which generate a system that could be repeated indefinitely, more units could conceivably be added to Smog in all directions.
Angeles area Smog Check shops were served with search warrants this
Responding to a rallying cry from San Francisco radio talk-show hosts, an estimated 3,000 Californians showed up on August 22 in Sacramento to protest the state's new smog check program.