Ozone problem Document

Certainly, photochemical air pollution is not merely a local problem. Indeed, spread of anthropogenic smog plumes away from urban centers results in regional scale oxidant problems, such as found in the NE United States and many southern States. Ozone production has also been connected with biomass burning in the tropics (79,80,81). Transport of large-scale tropospheric ozone plumes over large distances has been documented from satellite measurements of total atmospheric ozone (82,83,84), originally taken to study stratospheric ozone depletion. 

With the exception of calibration, the measurement problems that were apparent in 1970, at the time of publication of the fost air quality criteria document on photochemical oxidants, have essentially been solved for ozone. This remarkable achievement is the result of unstinting efforts by people working at epa s National Environmental Research Center, North Carolina the National Bureau of Standards private research contractors sponsored primarily by epa private instrument manufacturers the Jet Propulsion Laboratory of the California Institute of Technology the Air and Industrial Hygiene Laboratory, California Department of Health the Air Pollution Research Center of the University of California at Riverside and the California Air Resources Board (carb). 

The sad paradox is that, despite the primary importance of the latter problem convincingly substantiated in the scientific literature and the secondary role of the two former ones, UNCED documents have missed the primary importance of the following sequence of events socio-economic development (stimulated by growing population size) —> anthropogenic impact on the biosphere —> consequences of these impacts for the environment (climate, ozone, etc.). 

Our review here will highlight the role of semiconductor-initiated photochemistry as an environmental remediation method for the treatment of organic chemicals. While the role of sunlight-induced photochemistry in creating environmental problems such as urban photochemical smog and the polar ozone holes has been well documented, the potential applications of photochemical methods in resolving environmental problems are less obvious. 

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. 

Experience dictates that air pollution problems are not easily rationalized. Well-documented issues such as photochemical smog or the fate of atmospheric chlorofluorocarbons have revealed the potential for chemistry of considerable complexity, and even it seems for a different result (i.e. ozone enrichment or depletion) from not too dissimilar photochemical reactions. Smoke or add gases from combustion processes continue to cause concern, " and informed exchanges highlight the problems of identifying a source even for well-defined emissions. 

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