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4.1 – Air Quality Draft Environmental Impact Report February 2021 14800 W. Schulte Road Logistics Center 4.1-41 Health Impacts of Toxic Air Contaminants A substance is considered toxic if it has the potential to cause adverse health effects in humans, including increasing the risk of cancer upon exposure, or acute (immediate) and/or chronic (cumulative) non -cancer health effects. Potential construction-related health risk is qualitatively evaluated, and operational health risk is quantitatively evaluated for the Project, below. Construction Health Risk Project construction would result in emissions of DPM from heavy construction equipment and trucks accessing the site. DPM is characterized as a TAC by California. The Office of Environmental Health Hazard Assessment has identified carcinogenic and chronic noncarcinogenic effects from long-term exposure, but has not identified health effects due to short-term exposure to diesel exhaust. According to the Office of Environmental Health Hazard Assessment, HRAs, which determine the exposure of sensitive receptors to toxic emissions, should be based on a 70-year exposure period for the maximally exposed individual resident; however, such assessments should be limited to the period/duration of activities associated with a project (OEHHA 2015). Thus, the duration of the proposed construction activities would only constitute a small percentage of the total 70-year exposure period. Due to this relatively short period of exposure (10 months) and minimal DPM emissions on site, TACs generated by the Project would not result in concentrations causing significant health risks. In addition, diesel equipment would also be subject to CARB’s Airborne Toxic Control Measures for in-use off-road diesel fleets, which would minimize DPM emissions. Furthermore, the nearest sensitive receptor is located more than 1,500 feet from the Project site. Overall, based on the above considerations, the Project would not result in substantial TAC exposure to sensitive receptors in the vicinity of the Project, and impacts would be less than significant. Operational Health Risk An HRA was performed to estimate the Maximum Individual Cancer Risk, Chronic Hazard Index, and Acute Hazard Index for residential receptors as a result of emissions from the Project’s diesel yard truck and diesel forklifts; diesel-fueled fire pump; benzene, toluene, and xylene emissions from the diesel fuel storage tank; truck trips; and truck idling emissions. Results of the HRA during operation are presented in Table 4.1-13. Table 4.1-13. Operational Health Risk Assessment Results – Unmitigated Impact Parameter Units Impact Level CEQA Threshold Maximum Individual Cancer Risk Per Million 37.75 20 Chronic Hazard Index Index Value 0.009 1.0 Acute Hazard Index Index Value 0.0004 1.0 Source: SJVAPCD 2015a. Notes: CEQA = California Environmental Quality Act. See Appendix B. The results of the operational analysis demonstrate that the Project would be below the chronic and acute hazard index threshold of 1.0. However, the Project would exceed the maximum individual cancer risk of 20 in 1 million for the residential receptor. Thus, the impact would be potentially significant.