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