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City of Pleasanton—Hidden Canyon Residences and Preserve Draft EIR Air Quality FirstCarbon Solutions 3.2-9 https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480016/EIR/3 - Draft EIR/21480016 Sec03-02 Air Quality.docx These pollutants can have a wide range of health effects, such as respiratory issues, neurological damage, and reproductive problems. 10 Concentrations of TACs are also used as indicators of air quality conditions. Air pollutant human exposure standards are identified for many TACs, including the following common TACs relevant to development projects: PM, fugitive dust, lead, and asbestos. These air pollutants are called TACs because they are air pollutants that may cause or contribute to an increase in mortality or in serious illness or that may pose a hazard to human health. TACs are usually present in minute quantities in the ambient air; however, their high toxicity or health impact may pose a threat to public health even at low concentrations. TACs can cause long-term health effects (such as cancer, birth defects, neurological damage, asthma, bronchitis, or genetic damage) or short-term acute affects (such as eye watering, respiratory irritation, runny nose, throat pain, or headaches). TACs are separated into carcinogens and noncarcinogens based on the nature of the physiological effects associated with exposure to a particular TAC. Carcinogens are assumed to have no safe threshold below which health impacts would not occur. Cancer risk is typically expressed as excess cancer cases per million exposed individuals, typically over a lifetime exposure or other prolonged duration. For noncarcinogenic substances, there is generally assumed to be a safe level of exposure below which no negative health impact is believed to occur. These levels may vary depending on the specific pollutant. Acute and chronic exposure to noncarcinogens is expressed as a hazard index (HI), which is the ratio of expected exposure levels to an acceptable Reference Exposure Levels (RELs). Regional Air Quality and San Francisco Bay Area Air Basin Attainment Status The EPA and the ARB designate air basins where ambient air quality standards are exceeded as “nonattainment” areas. If standards are met, the area is designated as an “attainment” area. If there is inadequate or inconclusive data to make a definitive attainment designation, they are considered “unclassified.” National nonattainment areas are further designated as marginal, moderate, serious, severe, or extreme as a function of deviation from standards. The current attainment designations for the Air Basin are shown in Table 3.2-2. Currently in the Air Basin, 8-hour average ozone (both State and national), 1-hour average ozone (State), annual arithmetic mean PM10 (State), 24-hour average PM10 (State), annual arithmetic mean PM2.5 (State), and 24-hour average PM2.5 (national) are still in nonattainment status. The current standards are summarized in Table 3.2-2. 10 California Air Resources Board (ARB). 2023. ARB Identified Toxic Air Contaminants. https://ww2.arb.ca.gov/resources/documents/carb-identified-toxic-air-contaminants. Accessed October 10, 2024.