smog

Assorted References

• cause of fog  (in  fog (weather))

  ...that are always present in natural air (see video). This results as soon as the relative humidity of the air exceeds saturation by a fraction of 1 percent. In highly polluted air the nuclei may grow sufficiently to cause fog at humidities of 95 percent or less. Growth of the drops may be helped by the absorption of certain soluble gases, notably sulfur dioxide to...

• effect on plants  (in  plant disease (plant pathology): Toxic chemicals)

  ...Smaller amounts of unconsumed hydrocarbons are formed by combustion of fossil fuels (e.g., coal, oil, natural gas) and refuse burning. Ozone, peroxyacetyl nitrate, and other oxidizing chemicals (smog) are formed when sunlight reacts with nitrogen oxides and hydrocarbons. This pollutant complex is damaging to susceptible plants many kilometres from its source. Ozone and peroxyacetyl nitrate...

aspect of

• atmospheric processes and nitrogen cycle  (in  atmosphere (gaseous envelope): Nitrogen budget)

  ...processes associated with ultraviolet light from the Sun. The combustion of petroleum by motor vehicles also produces oxides of nitrogen, which enhance the natural concentrations of these compounds. Smog, which occurs in many urban areas, is associated with substantially higher levels of nitrogen oxides.

• London  (in  London (England, United Kingdom): Smog and air pollution)

  For years London was synonymous with smog, the word coined at the turn of the 20th century to describe the city’s characteristic blend of fog and smoke. The capital’s “pea-soupers” were caused by suspended pollution of smoke and sulfur dioxide from coal fires. The most severely affected area was the 19th-century residential and industrial belt of inner London—particularly the...

• Los Angeles  (in  Los Angeles (California, United States): Climate;

  ...blasts of desert heat and cold. However, the warm climate and the bowl-like alignment of the ranges also provide the ideal conditions for another well-known Los Angeles phenomenon: photochemical smog, which has remained a part of the landscape since the 1940s. Tough antipollution laws enacted by state and local authorities have helped reduce the motor-vehicle emissions contributing to smog...

  in  Los Angeles (California, United States): Municipal services;

  Los Angeles homeowners burned combustible trash in backyard incinerators until 1957, when, in an attempt to reduce the eye-searing attacks of smog that were then plaguing the region, the practice was ended. Now, each day the city’s sanitation trucks collect several thousand tons of household trash and dump it into large local sanitary landfills. Hillside areas covered with tinder-dry foliage in...

  in  respiratory disease (human disease): Air pollution )

  ...characterized for the first time in Los Angeles. The large number of automobiles in that city, together with the bright sunlight and frequently stagnant air, leads to the formation of photochemical smog. This begins with the emission of nitrogen oxide during the morning commuting hour, followed by the formation of nitrogen dioxide by oxygenation, and finally, through a complex series of...

• San Francisco  (in  San Francisco (California, United States): Transportation)

  Periodic smog, produced mainly by the automobiles in the area, is a serious concern. Freeway traffic is also a problem, as travel from the East Bay cities of Oakland and Berkeley and from Marin county to the north is confined to two great but overburdened bridges. The world’s longest high-level steel bridge, the San Francisco–Oakland Bay Bridge, is 4.5 miles (7.2 km) long; it was...

• air pollution
• city
• smog (atmosphere)