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Strategies for attainment of the carbon monoxide (CO) standard parallel strategies to reduce ROG. The Clean Air Act Amendments of 1977 (Public Law 95-95) mandate that areas not attaining the NAAQS be required to prepare non-attainment area plans (NAP). The Act clearly states criteria and timetables by which a NAP must be prepared. San Joaquin County was designated a non-attainment area for ozone, carbon monoxide, and particulates in late 1977 and a NAP was prepared. Since this plan did not show attainment of the NAAQS by 1982, according to the requirements of the Clean Air Act, the 1982 NAP revision was required. AIR QUALITY STANDARDS Air quality standards, shown on page 39, were established by state and federal agencies to assure that the health of living organisms would be protected from avoidable adverse conditions caused by air pollution. Although some of the state standards for oxidants , carbon monoxide, sulfur dioxide, and suspended particulates have the same averaging time as those of the federal standards, the numerical values of the standards are not the same. In these cases, compliance is based on the more stringent standard. AIR POLLUTION AND ITS SOURCES Air pollution in the study area is, for the most part, a product of civilization that becomes worse when the capacity of the atmosphere to dilute air pollutants is overburdened. Population centers, industry, and a high degree of dependence on the automobile cause pollutant emissions which complement, interact with, and furthyr increase natural background levels of certain atmospheric substances. Carbon monoxide, suspended particulate matter, oxides of sulfur, hydrocarbons (organic gases) and oxides of nitrogen are grouped as "primary pollutants" and are emitted directly into the atmosphere by their source. "Secondary pollutants," also called photochemical oxidants, are products of primary pollutants which undergo chemical changes in the atmosphere using the energy of sunlight. These changes or reactions are extremely complicated and are not throughly understood. It is known, however, that these reactions involve combinations of hydrocarbons (organic gases) , oxides of nitrogen and sunlight and they produce ozone, nitrogen dioxide, peroxyacetyl nitrates (PAN) and aldehydes, to name a few. Secondary pollutants, together with suspended particulate matter, form what is commonly referred to as "smog." Atmospheric concentrations of the primary pollutants occurring during the morning hours are usually inversely proportional to the mixing heights existing at that time and, given adequate exposure to sunlight, determine the intensity of photochemical smog that will be experienced downwind later in the day. The worst smog typically occurs on bright days with low inversions and low wind speeds. Conversely, little or no smog is formed on cloudy days with no inversions and brisk winds. 36