ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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5.1 AIR QUALITY about 3.6 miles from the project site.The nearest monitoring station for SO2 is at Bethel Island, about 15 miles from the project site. Monitoring of lead ended in 2003. The Stockton-Hazelton monitoring station is operated by the California Air Resources Board and the Bethel Island monitoring station is operated by the Bay Area AQMD. 5.1.1.3.3 Ozone Ozone is an end-product of complex reactions between volatile organic compounds (VOC) and NO,,in the presence of intense ultraviolet radiation. VOC and NO,,emissions from millions of vehicles and stationary sources,in combination with daytime wind flow patterns, mountain barriers,a persistent temperature inversion, and intense sunlight result in high ozone concentrations. For purposes of state and federal air quality planning,the San Joaquin Valley Air Basin is a nonattainment area for ozone. Maximum ozone concentrations at the Stockton-Hazelton monitoring station are usually recorded during the summer months. Table 5.1-3 shows the annual maximum one-hour and eight-hour ozone levels recorded at this station in Stockton during the period from 1998- 2007,as well as the number of days in which the state and federal standards were exceeded. The data show that the state ozone air quality standard was frequently exceeded during all years except in 2007. The federal 8-hour standard was also exceeded from time to time in six of the 10 years shown. The long-term trends of maximum one-hour ozone readings are shown in Figure 5.1-2 for the Stockton-Hazelton monitoring station in Stockton. The data show that compliance with the state ozone air quality standards has not been achieved in the area in the past 13 years. Trends of maximum and 3-year averages of the 4th highest daily concentrations of 8-hour average ozone readings2 at the Stockton-Hazelton station are shown in Figure 5.1-3. These levels are above the new 2008 federal 8-hour average standard (0.075 µg/m3) during the 11 years shown (1997-2007),except during period 2002-2005 for the 3-year average of the 4th highest daily concentration. TABLE 5.1-3 Ozone Levels at Stockton-Hazelton,Stockton, 1998-2007,(parts per million) 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 Highest 1-Hour Average 0.126 0.114 0.107 0.103 0.102 0.104 0.096 0.099 0.109 0.093 Highest 8-Hour Average 0.100 0.108 0.080 0.088 0.081 0.088 0.080 0.086 0.092 0.081 Number of Exceeding: State Standard 10 6 4 5 2 3 1 3 6 0 (0.09 ppm, 1-hour) Federal Standard 4 4 0 1 0 1 0 1 3 0 (0.08 ppm, 8-hour) Source: California Air Quality Data, Annual Summary, California Air Resources Board Note:The 1997 federal ozone standard has been replaced by the new 2008 standard of 0.075 ppm.A EPA final rule on the ozone standard became effective May 27, 2008. 2 The federal 8-hour ozone standard is based on this statistic. 5.1-8 SAC/371322/082410013(LEC_5.1_AIR_QUALITY.DOC)