ARCHIVED REPORTS_DRAFT ENVIRONMENTAL IMPACT REPORT

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improvement. The three basic designation categories are nonattainment, attainment, and unclassified.Unclassified is used in an area that cannot be classified on the basis of available information as meeting or not meeting the standards. In addition,the California designations include a subcategory of the nonattainment designation, called nonattainment-transitional. The nonattainment-transitional designation is given to nonattainment areas that are progressing and nearing attainment. The most current attainment designations for the San Joaquin County portion of the SJVAB are shown in Table 4.3-2 for each criteria air pollutant. On July 6, 2006,the EPA proposed redesignation for the SJVAB as a PM10 attainment area,based on the attainment of the national standard in the 2003 through 2005 period. The EPA finalized approval of the attainment designation on October 17,2006 (SJVAPCD 2006a). Wastewater Quality Control Facility Emissions The Manteca Wastewater Quality Control Facility(WQCF) emissions of criteria pollutants for 2004 are shown in Table 4.3-3. This is the latest data available from ARB (ARB 2006b). Table 4.3-3 WQCF Criteria Pollutant Emissions-2004 Pollutant Emissions(Tons per Year) Reactive Organic Gases 0.07 Oxides of Nitrogen 0.54 Carbon Monoxide 0.18 Sulfur Dioxide 0.58 Respirable Particulate Matter <0.01 Fine Particulate Matter <0.01 Source:City of Manteca 2004 EXISTING AIR QUALITY CONDITIONS—TOXIC AIR CONTAMINANTS Concentrations of TACs, or in federal parlance,hazardous air pollutants (HAPS), are also used as indicators of ambient-air-quality conditions. A TAC is defined as an air pollutant that may cause or contribute to an increase in mortality or in serious illness, or that may pose a hazard to human health. TACs are usually present in minute quantities in the ambient air; however,their high toxicity or health risk may pose a threat to public health even at low concentrations. According to the California Almanac of Emissions and Air Quality(ARB 2006a),the majority of the estimated health risk from TACs can be attributed to relatively few compounds,the most important being PM from diesel- fueled engines (diesel PM). Diesel PM differs from other TACs in that it is not a single substance,but rather a complex mixture of hundreds of substances.Although diesel PM is emitted by diesel-fueled internal combustion engines,the composition of the emissions varies depending on engine type, operating conditions, fuel composition, lubricating oil, and whether an emission control system is present. Manteca WQCF and Collection System Master Plans EIR EDAW City of Manteca 4.3-7 Air Quality