smog

(redirected from smoggiest)
Also found in: Dictionary, Thesaurus, Medical.

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
..... Click the link for more information.
. 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.
..... Click the link for more information.
: 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 ?
The Antelope Valley's air suffers from being downwind from two of the smoggiest places in the United States: the San Joaquin Valley and the Los Angeles area.
MTBE's manufacturers, represented by OFA, claim that "MTBE has been the workhorse of California's cleaner burning gasoline program and its use has contributed to a demonstrated reduction in air pollution in the state's smoggiest cities.
Using roadside test data from more than 9,000 vehicles, ARB estimates that the program cut 45 TPD of smog-forming hydrocarbon (HC) and (NOx) from the state's smoggiest areas in the summer of 1999.
Saying the nation's smoggiest region needs the toughest pollution controls, air-quality regulators for Southern California will push the state today to essentially ban the purchase of diesel-fueled school buses, garbage trucks and transit buses.
It's hardly an honor worth celebrating, but Los Angeles is, once again, headed toward being named the smoggiest place in the United States.
IT'S hardly an honor worth celebrating, but Los Angeles is, once again, headed to being named the smoggiest place in the United States.
Although California has dramatically cut smog over the last two decades, Southern California and the San Joaquin Valley still haven't met state or federal ozone standards and rank among the smoggiest regions in the nation.
Burke's initiative is in response to new research that found that children who grew up in the smoggiest areas of Southern California were more likely to have weaker lungs, a chronic problem that could make them more susceptible to health problems in their 40s and 50s.
The Department of Water and Power's environmental program was ostensibly set up to show how the nation's smoggiest city was responding to the growing public demand for more efficient and environmentally friendly energy sources.
The Los Angeles region has long held the title of smoggiest region, but only over the past decade have the health community, researchers and regulators begun to see particulate matter as a potentially more dangerous pollutant.
South Coast Air Quality Management District officials said they need the 2010 deadline - and the penalties it carried for violating it - to spur dramatic pollution cuts from vehicles, trucks, ports and other industrial polluters in the nation's smoggiest region.
Los Angeles - the nation's smoggiest city - likely will have until 2021 to meet a strict new standard for ozone emissions under a plan Environmental Protection Agency officials will announce today.