City of Fairfield - Hawthorne Mill Project Draft EIR/EIS Air Quality and Greenhouse Gas Emissions 3.2 - Air Quality and Greenhouse Gas Emissions 3.2.1 - Introduction This section describes the existing air quality setting and potential effects from project implementation on the site and its surrounding area. Michael Brandman Associates performed air quality modeling for the project; the model output is located in the Air Quality and Climate Change Model Output in Appendix B. Michael Brandman Associates also prepared a Health Risk Assessment, which is located in Appendix B. 3.2.2 - Affected Environment/Existing Conditions The project site is located in the City of Fairfield, which is within the San Francisco Bay Area Air Basin (Air Basin) portion of Solano County. The Air Basin comprises all or portions of the nine Bay Area counties, including the southwestern portion of Solano County. The northeastern portion of Solano County is located in the Sacramento Valley Air Basin. The project site is under jurisdiction of the Bay Area Air Quality Management District (BAAQMD). Regional Air Quality Air quality is a function of both the rate and location of pollutant emissions under the influence of meteorological conditions and topographic features. Atmospheric conditions such as wind speed, wind direction, and air temperature gradients interact with the physical features of the landscape to determine the movement and dispersal of air pollutant emissions and, consequently, their effect on air quality. Climate and Meteorology The western portion of Solano County is located within the Carquinez Strait subregion of the Air Basin. The Carquinez Strait runs from Rodeo to Martinez. It is the only sea level gap between San Francisco Bay and the Central Valley. The subregion includes the lowlands bordering the strait to the north and south, and includes the area adjoining Suisun Bay and the western part of the Sacramento- San Joaquin Delta as far east as Bethel Island. The subregion extends from Rodeo in the southwest and Vallejo in the northwest to Fairfield on the northeast and Brentwood on the southeast. Prevailing winds are from the west in the Carquinez Strait. During the summer and fall months, high pressure offshore coupled with low pressure in the Central Valley causes marine air to flow eastward through the Carquinez Strait. The wind is strongest in the afternoon. Afternoon wind speeds of 15 to 20 miles per hour (mph) are common throughout the strait region. Annual average wind speeds are 8 mph in Martinez, and 9 to 10 mph further east. Sometimes atmospheric conditions cause air to flow from the east. East winds usually contain more pollutants than the cleaner marine air from the west. In the summer and fall months, this can cause elevated pollutant levels to move into the central Bay Area through the strait. These high-pressure periods are usually accompanied by low wind speeds, shallow mixing depths, higher temperatures and little or no rainfall. Michael Brandman Associates 3.2-1 H:\Client (PN-JN)\2097\20970002\4 - DEIR\20970002_Sec03-02 AQ-GHG.doc City of Fairfield - Hawthorne Mill Project Air Quality and Greenhouse Gas Emissions Draft EIR/EIS Summer mean maximum temperatures reach about 90 degrees Fahrenheit (°F) in the subregion. Mean minimum temperatures in the winter are in the high 30s. Temperature extremes are especially pronounced in sheltered areas farther from the moderating effects of the strait itself, e.g. at Fairfield. The pollution potential of this area is often moderated by high wind speeds. Temperatures in the project area range from an average high of 89ºF in August to an average low of 37.6ºF in January. Rainfall averages almost 23 inches annually. General meteorological data for Solano County is measured at the Fairfield weather station. Inversions A primary factor in air quality is the mixing depth (i.e., the vertical air column available for dilution of contaminant sources). In general, air temperature decreases with distance from the earth’s surface, creating a gradient from warmer air near the ground to cooler air at elevation. Under normal circumstances, the air close to the earth warms as it absorbs surface heat and begins to rise. Winds occur when cooler air rushes in to take the place of the rising warm air. The wind and upward movement of air causes “mixing” in the atmosphere and can carry away or dilute pollution. Inversions occur when a layer of warm air sits over cooler air, trapping the cooler air beneath. Over the Air Basin, the frequent occurrence of temperature inversions limits mixing depth and, consequently, limits the potential for dilution. The main type of inversions that occur regularly in the Air Basin include shallow radiative inversions that occur primarily during the winter, and higher subsidence and advectional inversions that generally occur during the summer and fall. Emissions Inventory An emissions inventory is an accounting of the amount of air pollution generated by various emissions sources located within a specific area. To identify the sources and estimate the quantities of pollution, the California Air Resources Board (ARB), in cooperation with local air districts, other government agencies, and industry, maintains an inventory of California emission sources. Sources are subdivided into the four major emission categories: mobile, stationary, area-wide, and natural sources. Mobile sources include on-road sources and off-road mobile sources. The on-road emissions inventory, which includes automobiles, motorcycles, and trucks, is based on an estimation of population, activity, and emissions of the on-road motor vehicles used in California. The off-road emissions inventory is based on an estimate of the population, activity, and emissions of various off- road equipment, including recreational vehicles, farm and construction equipment, lawn and garden equipment, forklifts, locomotives, commercial marine ships, and marine pleasure craft. Stationary sources are large, fixed sources of air pollution, such as power plants, refineries, and manufacturing facilities. Stationary sources also include aggregated point sources. These include 3.2-2 Michael Brandman Associates H:\Client (PN-JN)\2097\20970002\4 - DEIR\20970002_Sec03-02 AQ-GHG.doc City of Fairfield - Hawthorne Mill Project Draft EIR/EIS Air Quality and Greenhouse Gas Emissions many small point sources, or facilities, that are not inventoried individually but are estimated as a group and reported as a single-source category. Examples include gas stations and dry cleaners. Each of the local air districts estimates the emissions for the majority of stationary sources within its jurisdiction. Stationary source emissions are based on estimates made by facility operators and local air districts. Emissions from specific facilities can be identified by name and location. Areawide sources include source categories associated with human activity that take place over a wide geographic area. Emissions from areawide sources may be either from small, individual sources, such as residential fireplaces, or from widely distributed sources that cannot be tied to a single location, such as consumer products usage, and dust from unpaved roads or farming operations (such as tilling). Natural, or non-anthropogenic, sources include source categories with naturally occurring emissions such as geogenic (e.g., petroleum seeps), wildfires, and biogenic emissions from plants. The 2008 emissions inventory for the portion of Solano County within the Air Basin is available in ARB’s 2009 Almanac Emission Projection Data. Table 3.2-1 summarizes the estimated 2008 emissions for the main pollutants of concern in the Air Basin portion of Solano County. Table 3.2-1: 2008 Inventory, San Francisco Bay Area Air Basin portion of Solano County Tons per Day Emission Category ROG NOx PM10 PM2.5 Stationary Sources 6.9 7.0 1.2 1.0 Areawide Sources 3.6 0.6 10.6 2.6 Mobile Sources 10.6 20.0 1.1 0.9 Natural Sources 2.6 — — — Total Solano County in San 23.7 27.6 12.9 4.5 Francisco Bay Area Source: ARB 2009a ROG. Mobile sources contributed approximately 45 percent of the 2008 reactive organic gases (ROG) emissions. Stationary sources accounted for approximately 29 percent of the 2008 emissions inventory, with the majority of emissions generated by waste disposal sources, followed by cleaning and surface coatings operations at 11 percent and 9 percent of the total ROG inventory for the Air Basin-portion of Solano County. NOx. Mobile sources generated the majority of oxides of nitrogen (NOx) emissions in Solano County at approximately 72 percent of the total NOx inventory. Stationary sources contributed approximately 25 percent of the NOx inventory, with stationary fuel combustion constituting the majority of stationary source emissions. Michael Brandman Associates 3.2-3 H:\Client (PN-JN)\2097\20970002\4 - DEIR\20970002_Sec03-02 AQ-GHG.doc City of Fairfield - Hawthorne Mill Project Air Quality and Greenhouse Gas Emissions Draft EIR/EIS PM10. For particulate matter smaller than 10 microns in diameter (PM10), areawide sources contributed more than 80 percent of the 2008 inventory. The main PM10-generating areawide sources include paved road dust, construction and demolition, and fugitive windblown dust. PM2.5. Areawide sources contributed almost 58 percent of the 2008 inventory of particulate matter smaller than 2.5 microns in diameter (PM2.5). Stationary sources and mobile sources generated approximately 22 percent and 20 percent of the inventory, respectively. The main PM2.5-generating areawide source was residential fuel combustion. Pollutants of Concern For reasons described below in the Regulatory Framework section, the criteria pollutants of greatest concern for the project area are ozone, PM10, and PM2.5. Although the Air Basin is in attainment of the carbon monoxide (CO) standards, there is a potential for CO hotspots on congested roadways and at congested intersections. Other pollutants of concern are toxic air contaminants, asbestos and greenhouse gases. The proposed project is not expected to produce air emissions containing hydrogen sulfide, sulfates, lead, and vinyl chloride; therefore, these pollutants will not be discussed.