NS-3092 - Zone Change for 1801 East Chestut Ave

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SANTA ANA REZONE PROJECT INITIAL STUDYFMITIGATED NEGATIVE DECLARATION meteorological conditions, CO concentrations near a congested roadway or intersection may reach unhealthy levels (i.e., adversely affect residents, school children, hospital patients, the elderly, etc.)." Because traffic congestion is highest at intersections where vehicles queue and are subject to reduced speeds, these hot spots are typically produced at intersection locations. None of the intersections near the project site would have peak-hour traffic volumes exceeding those at the intersections modeled in the 2003 AQMP.Additionally, the adjacent roadways are not located in an area where vertical or horizontal atmospheric mixing is substantially limited, such as a tunnel or overpass. Furthermore, there are no factors unique to the local meteorology to conclude that this intersection would yield higher CO concentrations if modeled in detail. Therefore, the operational CO impact would be less than significant. Toxic Air Contaminants Impact to Sensitive Receptors The proposed project would generate TACs, such as DPM, during construction due to the use of off- road construction equipment and haul trucks. DPM is represented as exhaust emissions of PM10 and PM2.5.As shown in Table 3, project construction would emit at most 8.76 and 2.33 pounds per day of PM1a and PM2.5.As discussed in Impact 2.3(b), emissions during construction would not exceed the SCAQMD's significance thresholds for PM2 5 and PM,o and would not be expected to result in concentrations that could exceed ambient air quality standards or contribute substantially to an existing exceedance of an ambient air quality standard. In addition, the Office of Environmental Health Hazard Assessment (OEHHA)'s risk assessment methodology is designed to be health-protective and assumes chronic exposure over a 30-year residential receptor duration to estimate maximum individual cancer risk, However, the construction activities for the proposed project are short-term in nature, with an estimated duration of only three months. Given this limited timeframe, exposure to DPM from diesel-powered construction equipment would be brief and substantially less than the multi-year exposure period assumed in OEHHArs conservative risk models. As a result, even if sensitive receptors are located near the construction site, the actual health risk from construction emissions would be orders of magnitude lower than a typical 30-year chronic exposure scenario. Based on this brief construction window and the temporary nature of emissions, the project's construction-related health risks are considered less than significant. Post-construction, the proposed project would be used as an overflow parking lot. The vehicles that access the site would largely be gasoline or electricity powered and would not be a significant source of DPM emissions. Therefore, the proposed project's operation-related health risks are considered less than significant. 27 California Office of Environmental Health Hazard Assessment(OFHHA).2015.Air Taxies Hot Spot Program Risk Assessment Guidelines—Guidance Manual for Preparation of Health Risk Assessments.Website: https:lloeh ha.ca.govlmedia/d own loads/cm rl2015guidancemanua1.pdf.Accessed July 25,2025. FCS 35 NIIPd://adeeinnovations A.repaint.eam/silesfPubfkalianaSile/Shared 0ac1me1[;fPllbl06ons/Client(PNJN)/0327/0327d 7/ISMND/0327S047 santa And R-z Pr.,Qr4W.atce No. NS-3092 Page 47 of 118