Photochemistry photochemical smog

Basic rate information permits one to examine these phenomena in detail. Leighton [2], in his excellent book Photochemistry of Air Pollution, gives numerous tables of rates and products of photochemical nitrogen oxide-hydrocarbon reactions in air this early work is followed here to give fundamental insight into the photochemical smog problem. The data in these tables show low rates of photochemical consumption of the saturated hydrocarbons, as compared to the unsaturates, and the absence of aldehydes in the products of the saturated hydrocarbon reactions. These data conform to the relatively low rate of reaction of the saturated hydrocarbons with oxygen atoms and their inertness with respect to ozone. 

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. 

The effects of photochemical smog/urban air pollution remain on the political agenda owing to their potential impact on human health and the economy. In summary, urban photochemistry is not substantially different from tropospheric photochemistry. It is the range and concentrations of the VOCs involved in oxidation coupled to the concentration of NO c and other oxidants that lead to a large photochemical turnover. 

Photochemistry of course plays a crucial role in the whole of tropospheric atmospheric chemistry, not just in locally confined events such as those involving acid deposition discussed above, and in the weU-documented photochemical smog of Californian cities, which is now a local problem of very widespread incidence throughout the world. 

Photochemistry, chemistry caused by light, is responsible for many of the atmospheric reactions that determine the quality of our air. Photochemical smog is the name given to the red-brown haze that can form over cities under certain weather conditions. Nitrogen (as N2) and oxygen... 

The photochemical smog in the atmosphere is a result of chemical and photochemical reactions n ghe air between oxides of nitrogen, oxygen and hydrocarbons. The photochemistry of smog involves very complicated reactions which are intensively investigated by several laboratories round the world. 

Finally, enrichment of isotopic species has been achieved for a number of atoms and molecules using an appropriate monochromatic light source that preferentially excites an isotopic species of interest in mixtures of other isotopic species. The photochemistry associated with isotopic enrichment is briefly described in Chapter VIII. Great efforts have been made recently to obtain information on the detailed photochemical processes involving smog formation, stratospheric pollution, and atmospheres of other planets, and brief discussions of these subjects are also presented in the chapter. 

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