6 - GPA19-01; AA19-01_651 W SUNFLOWER AVENUE

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Legacy Sunflower Apartments Page 43 Mitigated Negative Declaration – March 14, 2019 The local air quality emissions from project construction activities were analyzed using the SCAQMD’s Mass Rate Localized Significant Threshold Look-up tables and the methodology described in LST Methodology, prepared by SCAQMD. The emission thresholds were calculated based on the Central Orange County source receptor area (SRA) 17 and a disturbance value of two acres per day. According to LST Methodology, any receptor located closer than 25-meters (82 feet) shall be based on the 25-meter thresholds. The nearest sensitive receptors are the students and administrators at the Taft Elementary School located adjacent to and north of the project and residents of the existing multi- family residential dwelling units adjacent to and east of the site. Therefore, the SCAQMD Look-up tables for 25-meters was used. Table 7 shows the on-site emissions from the CalEEMod model for the different construction phases and the calculated emissions thresholds. Table 7 Local Construction Emissions at the Nearest Receptors As shown in Table 7, none of the analyzed criteria pollutants would exceed the SCAQMD's local emissions thresholds at the nearest sensitive receptor. Therefore, the project construction emissions meet the LST for construction thresholds and would be less than significant. Construction-Related Toxic Air Contaminant Impacts The greatest potential for toxic air contaminant emissions from the project would be due to diesel particulate emissions due to the operation of heavy equipment operations during construction of the project. According to SCAQMD methodology, health effects from carcinogenic air toxics are usually described in terms of “individual cancer risk”. “Individual Cancer Risk” is the likelihood that a person exposed to concentrations of toxic air contaminants over a 30-year lifetime would contract cancer, based on the use of standard risk-assessment methodology. Given the relatively limited number of heavy-duty construction equipment and the short-term construction schedule, the project would not result in a long-term (i.e., 30 years) substantial source of toxic air contaminant emissions and corresponding individual cancer risk. Furthermore, construction-based particulate matter (PM) emissions (including diesel exhaust emissions) do not exceed local or regional thresholds. Therefore, no significant short-term toxic air contaminant impacts would occur during project construction. Long-Term Operational Emissions The on-going operation of the project would increase the generation of long-term air quality emissions. This increase would mainly be due to emissions from the project-generated vehicle trips. The following Activity On-Site Pollutant Emissions (pounds/day) NOx CO PM10 PM2.5 Demolition 33.20 21.75 1.78 1.56 Site Preparation 15.54 8.69 3.24 2.05 Grading 26.39 16.05 3.91 2.50 Building Construction 19.19 16.85 1.12 1.05 Paving 10.84 12.26 0.58 0.53 Architectural Coating 1.53 1.82 0.09 0.09 SCAQMD Thresholds 115 715 6 4 Exceeds Threshold? No No No No 6-65