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5.1 AIR QUALITY <br /> PM2.5 is also measured at the Stockton-Hazelton monitoring station. Maximum 24-hour <br /> average readings have met EPA's federal standard (35 µg/m3) that is applied to the 3-year <br /> average 98th percentile reading, since 2002. <br /> Table 5.1-9 shows the federal air quality standards for PM2.5, maximum levels recorded at the <br /> Stockton-Hazelton monitoring station in Stockton during 1998-2007, and 3-year averages for <br /> the same period. Annual average PM2.5 levels have exceeded the state standard during <br /> monitoring years,but have been below the federal standard since 2003. As for PM1o, PM2.5 is <br /> measured only once every 6 days, so expected exceedances are 6 times the number of <br /> measured exceedances. The San Joaquin Valley Air Basin is considered a nonattainment area <br /> for the state PM2.5 standard but the attainment status for the federal PM2.5 standard has not <br /> yet been determined. <br /> The trend of federal annual average PM2.5 levels is plotted in Figure 5.1-11, and the trend of <br /> maximum 24-hour average levels is plotted in Figure 5.1-12. <br /> TABLE 5.1.9 <br /> PM2.5 Levels Stockton-Hazelton,Stockton, 1998-2007(µg/m3) <br /> 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 <br /> Highest 24-hour Average * 101 78 76 64 45 41 63 47 52 <br /> Number of Days Exceeding: <br /> Federal Standard <br /> (35 Pg/M3, 24-hour) 15.3 3 5.9 0 0 0 0 0 0 <br /> 98th Percentile * 79 55 58 50 41 36 44 42 48 <br /> 3-yr Average, 98th Percentile * * 64 54 50 42 40 41 45 <br /> Annual Arithmetic Mean * 19.7 15.5 13.9 16.7 13.6 13.2 12.5 13.1 12.9 <br /> 3-yr Annual Average * * 16.4 15.3 14.7 14.5 13.1 12.9 12.8 <br /> (Federal Std = 15 Pg/m3) <br /> Source: California Air Quality Data,Annual Summary, California Air Resources Board <br /> *There were insufficient(or no)data available to determine the value. <br /> 5.1-18 SAC/371322/082410013(LEC_5.1_AIR_QUALITY.DOC) <br />