SU0004916 - Laserfiche WebLink

Home Browse Search

4.12 AIR QUALITY This section includes an evaluation of the air quality impacts of the College Park project in terms of construction emissions,toxic air contaminants(IACs), odors,local mobile source carbon monoxide(CO)concentrations,and long-term regional emissions. The information contained in this section is based on documents prepared by the San Joaquin Valley Air Pollution Control District(SJVAPCD),U.S.Environmental Protection Agency(EPA), California Air Resources Board(ARB), and National Oceanographic and Atmospheric Administration(NOAA), trip generation and level of service(LOS)information from the traffic section prepared for this Draft EIR(Section 4.11,"Transportation'),and air quality modeling conducted for this analysis(ARB-approved URBEMIS7G and CALINE4 models). The output of the air quality modeling is available for review by the public at the San Joaquin County Community Development Department, 1810 East Hazelton Avenue, Stockton,California 95205. 4.12.1 PHYSICAL SETTING The College Park project site is located in the San Joaquin Valley Air Basin(SJVAB),which is under the jurisdiction of the SJVAPCD. Applicable air quality regulations and the factors affecting air quality conditions at the proposed project site are discussed below. TOPOGRAPHY, METEOROLOGY AND DISPERSION Dispersion of air pollution in an area is determined by such natural factors as topography,meteorology,and climate,coupled with atmospheric stability and the presence of inversions. The factors affecting the dispersion of air pollution with respect to the SJVAB are discussed below. Topography The SJVAB occupies the southern half of the Central Valley and is approximately 250 miles in length and on average 35 miles in width. The Coastal Mountain Range is located on the western border of the SJVAB. The San Emigdio Mountains,which are part of the Coastal Mountain Range, and the Tehachapi Mountains,which are part of the Sierra Nevada Mountain Range, are located to the south of the SJVAB. The Sierra Nevada Mountain Range forms the eastern border of the SJVAB and extends in a northwesterly direction,encompassing Mt. Whitney with an elevation of 14,495 feet. The terrain in the SJVAB is basically flat with a downward gradient to the northwest. " Meteorology and Climate The climate of the SJVAB is strongly influenced by mountain ranges. The mountain ranges to the west and south �- induce winter storms from the Pacific Ocean to release precipitation on the western slopes,thus producing a partial rain shadow over the valley, and blocking the free circulation of air to the east,which results in the entrapment of stable air in the valley for extended periods during the cooler half of the year. Winter in the SJVAB is mild and fairly humid,and summer is hot, dry, and cloudless. The climate is a result of the topography and the strength and location of a semipermanent, subtropical high-pressure cell. During summer,the Pacific high-pressure cell is centered over the northeastern Pacific Ocean,resulting in stable meteorological conditions Y and a steady northwesterly wind flow. Upwelling of cold ocean water from below to the surface resulting from the northwesterly flow produces a band of cold water off the California coast. In winter,the Pacific high-pressure cell weakens and shifts southward,resulting in wind flow offshore,the absence of upwelling,and the occurrence of storms. The annual temperature,humidity,precipitation, and wind patterns reflect the topography of the SJVAB and the strength and location of a semipermanent, subtropical high-pressure cell. Summer temperatures that often exceed 100 degrees Fahrenheit(°F)coupled with clear skies are favorable to ozone(O;)formation. Most precipitation in the valley occurs during winter because of the presence of storms. The winds and unstable atmospheric College Park at Mountain House Specific Plan III Draft EIR EDAW San Joaquin County 4.12-1 Air Quality