5A Public Hearing 2019 0204 - Laserfiche WebLink

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3.0 ENVIRONMENTAL CHECKLIST City of San Leandro 1388 Bancroft Avenue Project November 2018 Initial Study/Mitigated Negative Declaration 3.0-19 A health risk screening was completed for the project to analyze the potential impacts on the closest sensitive receptors to the project site from the project’s estimated construction emissions using the CARB Hotspots Analysis and Reporting Program, Air Dispersion Modeling and Risk Tool (ADMRT) version 18159, following the Office of Environmental Health Hazard Assessment (2015) Air Toxics Hot Spots Program – Risk Assessment Guidelines. The ADMRT incorporates air dispersion modeling from specified pollutant sources using the EPA AERMOD Gaussian model, calculation of local concentrations, and evaluation of the resulting health risks for specified sensitive receptors. The ADMRT output files, model inputs, and assumptions are included in Appendix AQ. Inputs to the screening model included CARB meteorological data from the Oakland International Airport station, terrain data from the CARB San Leandro 30-meter digital elevation model file, and the project’s estimated construction maximum daily and total emissions of on-site exhaust PM10 from the California Emissions Estimator Model (CalEEMod). Diesel PM comprises a complex mixture of particles, 90 percent of which are less than 1 micron in size. The health risk screening conservatively assumes that 100 percent of the construction exhaust PM10 generated on the project site is diesel PM. The heaviest emissions of exhaust PM10 would occur during demolition and earthmoving activities, approximately 2 months. To be conservative, health risks were evaluated for a 6-month exposure to the peak emissions of exhaust PM10 generated on the project site (peak emissions would occur during the demolition phase). The BAAQMD CEQA Air Quality Guidelines recommend thresholds for assessing community health risks for individual projects of a maximum increased excess cancer risk of 10 in one million. For the closest sensitive receptors to the project site (a single-family home adjacent to the site to the east), the health risk screening estimated that the maximum increased excess cancer risk from unmitigated project-generated construction diesel PM, assuming six months of demolition, would be 95 in one million, above the BAAQMD threshold, and mitigation would be required. EPA-certified Tier 4 off-road diesel engines have exhaust reduction systems that reduce diesel PM emissions by more than 85 percent compared to earlier engines, and most construction equipment sold in the United States since 2015 is Tier 4 certified. Older construction equipment retrofitted with CARB-verified level 3 diesel particulate filters also reduces diesel PM emissions by more than 85 percent. Mitigation measure MM AQ-2 would require the use of EPA-certified Tier 4 engines or the use of CARB-verified level 3 diesel particulate filters on all diesel off-road construction equipment with more than 50 horsepower. With implementation of mitigation measure MM AQ-2, the health risk screening model estimated that the maximum increased excess cancer risk from mitigated project-generated construction diesel PM would be 2.1 in one million, which is below the BAAQMD threshold. Therefore, the impact on community health risks from project construction–generated diesel PM would be less than significant with mitigation incorporated. The BAAQMD has also determined that localized concentrations of PM2.5 could pose a health risk. CARB has not designated PM2.5 as a TAC, and cancer or health risk exposure levels have not been established. The BAAQMD has recommended thresholds for a maximum increase in PM2.5 concentration resulting from a project of 0.3 micrograms per cubic meter annual average. Using the unmitigated maximum daily and total on-site project construction PM2.5 emissions (including both exhaust and fugitive dust sources), the health risk screening model estimated that the maximum increased annual average concentration of PM2.5 at the closest sensitive receptors would be 0.1 micrograms per cubic meter. Therefore, the impact on community health risks from project construction– generated PM2.5 would be less than significant.