ARCHIVED REPORTS_1991_1 - Laserfiche WebLink

Home Browse Search

To o r by and Climate The study area lies within the San Joaquin Valley, w1uch is bounded by the Sierra Nevada range on the east and the coastal mountain range on the west. 7he Carquinez Strait is a sea level gap in the coastal range;the strait is 55 miles west of the study area, and the intervening terrain is flat. The prevailing wind direction in the study area is from the west, resulting from marine breezes through the Carquinez Strait. Figure 13-1 shows prevailing summer wind patterns, and Table 13-1 shows average climatological data for San Joaquin County. Air QuaW Standards The Federal Clean Air Act established air quality standards for several pollutants and requires areas that violate these standards to prepare and hnplement plans to achieve the standards by certain deadlines. State and federal air quality standards are shown in Table 13-2. The deadline for attaining both the ozone and carbon monoxide (CO) standards is December 31, 1987 Both the State of California and the federal government have established a variety of ambient air quality standards. The state one-hour ozone standard is 0.10 ppm (by volume), not to be equalled or exceeded. Tyle federal one-hour ozone standard is 0.12 ppm, not to be exceeded more than three times in any three-year period. State and federal CO standards have been set for both one-hour and eight-hour averaging times. The state one-hour CO standard is 20 ppm, while the federal one-hour CO standard is 35 ppm. Both state and federal standards are 9 ppm for the eight-hour averaging period. State CO standards are phrased as values not to be exceeded more than once per year. Air Q itv onitoring Data Urban emission sources in San Joaquin County are a primary source of an existing air quality problem. The federal and state air quality standards for ozone and CO are currently being exceeded (See Table 13-1). The federal ozone standard has been violated at all of the County ozone monitoring stations that have operated since 1978. The ozone standard was violated on 21 days in 1978 at the Union Island station and on 13 days in 1978 at the Ham Lane station in Lodi. Except for these two occurrences, the federal ozone standard was violated a maximum of six days at any one station during any one year. both of the currently operating ozone monitoring stations (Hazelton and Mariposa Streets) recorded violations of the federal ozone standard in 1984. Only the Mariposa monitoring station recorded violations of the standard in 1985 and 1986 Tyne federal and state eight-hour CO standards have been exceeded up to two days per year at the Hazelton Street monitoring station and up to nine days per year at the 15