Photochemistry of the Polluted Troposphere

Publisher Website
Google Scholar
Abstract
OH and HO2 are greatly important in photochemical smog formation. OH was measured directly in urban air. Determination of the concentration-time profiles of OH under a variety of conditions in simulated and real atmospheres will greatly enhance the understanding of photooxidation processes occurring in these complex mixtures. Development of sufficiently sensitive detection techniques for other free radical species such as HO2 will prove of great value. Detailed quantitative data on the irradiation of simulated and real polluted atmospheres (even on the stable products) remain sparse, especially for reactions of aromatic hydrocarbons. Virtually no quantitative information, necessary for the validation of computer models, is available on the yields of such species as HONO and H2O2. The complex chemistry of photochemical smog must include heterogeneous and homogeneous reactions. Studies of physical and chemical synergisms arising from the introduction of SO2 into the HC-NOx-Ox [oxidant]-UV system are of top priority, since the rate of photooxidation of gaseous SO2 to particulate sulfate is greatly enhanced in ambient photochemical smog. Synergisms in these systems may also have important biological consequences. Physical and chemical transformations occurring in the HC-NOx-Ox-UV system must be far better understood; such knowledge is a cornerstone of rational, cost-effective air pollution control strategies. While this overall research goal is being pursued, existing knowledge must be utilized to strike an acceptable balance among needs in energy, economics and air quality.