Photochemical smog in Los Angeles

Edinger, J. G. Vertical distribution of photochemical smog in Los Angeles basin. Environ. Sci. Technol. 7 247-252. 1973. 

Before extensive application of these plume models, Frenkiel used a puff model to study photochemical smog in Los Angeles (5). A point source was assumed to be centered within each four-mile-square in the... 

Figure 16.16 Days each year in which ozone levels have exceeded 120 ppbv, indicating a distinct downward trend in the occurrence of photochemical smog in Los Angeles. Based upon data finm the U.S. Environmental Protection Agency.

Solvents in Photochemical Smog Formation, Los Angeles Air Pollution Control District, July 1966. 

Thus this type of urban air pollution is called photochemical smog of Los Angeles type. This air pollution phenomenon is very frequent in many Asian cities, especially those in subtropical and tropical zone. 

Three properties of photochemical smog were evident first in Los Angeles eye irritation haze (aerosol) formation and the d adation of rubber products. All three are associated with oxidants, although aerosols can also be formed by other pollutants, particularly sulfur dioxide. 

Descriptions of the vertical and horizontal distributions of photochemical smog in the Los Angeles basin (southern coastal air basin) during... 

One of the first atmospheric chemical cycles to be well documented involves the production of high levels of ozone and photochemical smog. This cycle is ubiquitous in polluted air in any urban area, but was first studied in detail in Los Angeles, California, where the problem is particularly bad due to the high vehicle density and low ventilation rate of the Los Angeles Basin. The set of all possible atmospheric reactions that occur is complex, so only the basic 03-N0x cycle and one representative hydrocarbon pathway are presented here. 

Photochemical oxidants are mainly produced during power generation, in industrial operations and are also from natural sources. The singlet oxygen (3-6) is to alargeextent related to automobile exhaust, which is the main cause of the photochemical smog in the Los Angeles area. 

The service life of plastics and other polymeric materials is a particular problem in Los Angeles and Tokyo because of the special climatic conditions for formation of photochemical smog. This situation is by no means confined to the USA and Japan. Photochemical smog and environmental corrosion of polymers is commonly observed in some European cities, notably Madrid, Athens and London. In Stockholm where air pollution is at a low level these problems are presently not seen so serious. 

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