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Summary of 2018 Spotorno Ranch Air Quality Analysis <br />March 22, 2021 <br />Page 8 <br /> <br />Phases <br />On-site DPM <br />(grams/m2-sec) <br />Off-site DPM <br />from SR-12 West to project <br />(grams/sec) <br />2020 8.86E-08 1.43E-05 <br />Source: CalEEMod and FirstCarbon Solutions <br /> <br />Estimates of Health Risks and Hazards from Project Construction <br />The estimated health and hazard impacts at the maximum impacted off-site sensitive receptor from the <br />project’s construction emissions are provided in Table 5. The maximum impacted off-site sensitive <br />receptor (MIR) was found at an existing residence located approximately 68 feet south of the site at 2315 <br />Westbridge Lane. <br />Table 5: Estimated Health Risks and Hazards During Construction—Unmitigated <br />Health Impact Metric <br />Cancer Risk <br />(risk per million) <br />Chronic <br />Non-Cancer <br />Hazard Index(2) <br />Annual PM2.5 <br />Concentration <br />(µg/m3) <br />Risks and Hazards at the Maximum Impacted Off-site Sensitive Receptor (MIR): (1) <br />Risks and Hazards at the Maximum Impacted <br />Sensitive Receptor (MIR): Infants 16.5 0.01 0.1 <br />Risks and Hazards at the Maximum Impacted <br />Sensitive Receptor (MIR): Child 2.5 0.01 0.1 <br />Risks and Hazards at the Maximum Impacted <br />Sensitive Receptor (MIR): Adult 0.4 0.01 0.1 <br />BAAQMD Significance Threshold 10.0 1.0 0.3 <br />Exceeds Individual Source Threshold? Yes (Infants) No No <br />Notes: <br />1 Maximum impacted sensitive receptor is a residence located 2315 Westbridge Lane, which is 68 feet south of the <br />project site. <br />2 Chronic non-cancer hazard index was estimated by dividing the annual DPM concentration (as PM2.5 exhaust) by the <br />REL of 5 µg/m3. <br />Source: CalEEMod and FirstCarbon Solutions <br /> <br />As shown in Table 5, the cancer risks for infants at the MIR would exceed the BAAQMD’s recommended <br />threshold of significance for cancer risk. Therefore, mitigation is required to reduce potential impacts to <br />nearby sensitive receptors from project construction. <br />MM AIR-4 would require all off-road construction equipment in excess of 50 horsepower used on-site by <br />the developer or contractors be equipped with engines meeting the EPA Tier III off-road engine emission <br />standards. This would reduce cancer risks and hazards associated with construction emissions. Table 6