3_Exhibit B - Laserfiche WebLink

2/6 Outdoor Air Quality - To the maximum extent practicable, individual and common exterior open space, including playgrounds, patios, and decks, shall either be shielded from the source of air pollution by buildings or otherwise buffered to further reduce air pollution for project occupants. This HRA is prepared in accordance with the requirements in MM 4.B-4, above. Because the Project would not introduce any new stationary sources of TAC emissions, such as a standby diesel generator, the proposed project residents would only be exposed to TAC emissions from existing and foreseeable future sources in the Project’s vicinity. Health risk impacts from these sources are summarized in the memorandum. BAAQMD HEALTH RISK THRESHOLDS The BAAQMD recommends health risk screening thresholds in the current CEQA Guidelines, which were updated in May 2017.1 The applicable screening thresholds for the Project are summarized below: BAAQMD Health Risk Screening Thresholds Risks and Hazards for New Receptors Cumulative Threshold Cancer Risk Increased cancer risk of >100 in a million (from all local sources) Hazard Index (HI) Increased non-cancer risk of >10 HI (from all local sources) (chronic) Ambient PM2.5 Concentration Ambient PM2.5 increase: > 0.8 µg/m3 annual average (from all local sources) Abbreviations: HI = Hazard Index PM2.5 = Particulate Matter less than 2.5 microns µg/m3 = micrograms per cubic meter. Reference: BAAQMD, 2017. CEQA Air Quality Guidelines. May. CUMULATIVE HEALTH RISK ASSESSMENT In accordance with BAAQMD CEQA guidelines and Recommended Methods for Screening and Modeling Local Risks and Hazards, Ramboll conducted a cumulative HRA for the new onsite sensitive receptors (the Project’s residents). The BAAQMD recommends evaluating the potential sources of TAC emissions within 1,000 feet of sensitive receptors and provides tools with conservative estimates of impacts from these sources, including a stationary source tool and raster files for railways major streets, and highways. The cumulative assessment tabulates the health risk impacts from existing offsite sources (stationary and mobile) at the on-site sensitive receptor locations. The HRA considered any foreseeable future sources of TAC sources in the Project’s vicinity. In addition to the evaluation of each single source, the combined health risk from all sources emitting TAC and particulate matter less than 2.5 microns in size (PM2.5) are evaluated. 1 BAAQMD, 2017. California Environmental Quality Act (CEQA) Air Quality Guidelines. May.