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r <br />5.8 Air Quality <br />+ 5.8.1 Environmental Setting <br />4- Air quality is dependent upon the source location, the amount <br />and type of pollutants emitted, and on the subsequent atmospheric <br />dispersion of the pollutants. Schematically, air quality may be <br />described as follows: <br />I: <br />DISPERSION <br />LI_ <br />o Emissions + Meteorology + Air Chemistry --i► Air Quality <br />SOURCES RECEPTORS <br />cr: <br />i. <br />e <br />There are several distinctions made in the identification of <br />air pollutants. One distinction made is between primary and secondary <br />air pollutants. Primary pollutants are those pollutants that are <br />emitted directly from sources. Carbon monoxide, hydrocarbons (organic <br />gases), oxides of nitrogen, sulfur dioxide, and particulate matters are <br />primary pollutants. Secondary pollutants are those pollutants formed by <br />chemical and photochemical reactions in the atmosphere. Photochemical <br />oxidants and nitrogen dioxide (NO x2) are principal secondary pollutants. <br />Primary and secondary pollutants are transported and dispersed <br />by meteorological processes. Meteorological factors important to the <br />transport of air pollution within the South Coast Air Basin, in which <br />the proposed project site is located are wind speed and direction, and <br />the presence of atmospheric temperature inversions. With very light <br />wind speeds (average of 5.7 miles per hour) the basin atmosphere has a <br />limited capability to disperse air pollutants horizontally. As shown in <br />Figure 29, the dominate daily wind pattern is a northeasterly daytime <br />sea breeze and southwesterly nighttime land breeze. <br />75D--268 <br />