ARCHIVED REPORTS LEC APPLICATION FOR CERTIFICATION

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5.1 AIR QUALITY WPCF to the north,the existing STIG plant to the west, and a vector control facility to the south. Also south of the project site is Dredger Cut,which discharges into White Slough at the confluence with Bishop Cut. The project site is nearly level, at an elevation approximately at sea level. Essentially flat terrain extends for many miles on all sides of the project site. The project site is located in the San Joaquin Valley Air Pollution Control District (SJVAPCD). 5.1.1.2 Climate and Meteorology The climate of the San Joaquin Valley is characterized by hot summers,mild winters, and small amounts of precipitation.The major climatic controls in the Valley are the mountains on three sides and the semi-permanent Pacific High pressure system over the eastern Pacific Ocean. The Great Basin High pressure system to the east also affects the Valley,primarily during the winter months. These synoptic scale influences result in distinct seasonal weather characteristics, as discussed below. The Pacific High is a semi-permanent subtropical high-pressure system located off the Pacific Coast. It is centered between the 140°W and 150°W meridians,and oscillates in a north-south direction seasonally. During the summer, it moves northward and dominates the regional climate,producing persistent temperature inversions and a predominantly southwesterly wind field. Clear skies,high temperatures, and low humidity characterize this season. Very little precipitation occurs during summer months,because migrating storm systems are blocked by the Pacific High. Occasionally,however,tropical air moves into the area and thunderstorms may occur over the adjacent mountains. In the fall,the Pacific High weakens and shifts southwestward toward Hawaii,and its dominance is diminished in the San Joaquin Valley. During the transition period,the storm belt and zone of strong westerly winds also moves southward into California. The prevailing weather patterns during this time of year include storm periods with rain and gusty winds, clear weather that can occur after a storm or because of the Great Basin High pressure area, or persistent fog caused by temperature inversion. Precipitation and temperature data have been recorded at the meteorological monitoring station located in Lodi, approximately 5.7 miles east-northeast of the project site. In summer (June,July,and August), daily high and low temperatures at the project area average 89.7 and 55.0°F (degrees Fahrenheit),respectively. In winter (December,January,and February), daily high and low temperatures are about 56.6 and 38.8°F,respectively.1 The average annual rainfall at the project site is about 17.6 inches,of which about 81% occurs between November and March. Between rainstorms,skies are fair,winds are light, and temperatures are moderate. Air quality is determined primarily by the type and amount of pollutants emitted into the atmosphere,the topography of the air basin,and local meteorological conditions. In the project area, stable atmospheric conditions and light winds can provide conditions for pollutants to accumulate in the air basin when emissions are produced. The predominant winds in California are shown in Appendix 5.113,Figures 5.1B-1A through 5.113-11). As 1 Desert Research Institute,Western Regional Climate Center.2008.Western U.S.Climate Historical Summaries,Site Accessed May 2008.URL:http://www.wrcc.dri.edu/Climsum.htmi 5.1-2 SAC/371322/082410013(LEC_5.1_AIR_QUALITY.DOC)