2014-028 - Approving General Plan Amendement No. 2014-01

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CW of Santa Ana -Park View at Town and Country Manor Draft EIR Localized Construction Emissions Impact 4.2 -2 The project would exceed the SCAQMD localized significance thresholds during construction. Thresholds of Significance The SCAQMD Governing Board adopted a methodology for calculating localized air quality impacts through localized significance thresholds (LSTs), which is consistent with SCAQMD's Environmental Justice Enhancement Initiative I -4. LSTs represent the maximum emissions from a project that would not cause or contribute to an exceedance of the most stringent applicable State or national ambient air quality standard. To facilitate the localized assessment process, the SCAQMD LST methodology (SCAQMD 2003) provides a series of look -up tables that contain LSTs for the Source Receptor Areas (SRAs) within the basin. If onsite construction emissions are above the LST, then the project would be considered to have a significant air quality impact. This methodology applies to projects up to 5 acres in size. Mitigation measure AQ -3 restricts grading activities (the phase with the greatest emissions) to five acres or less per day. Therefore, pursuant to personal communication with the SCAQMD, this approach is valid. The LSTs were obtained from the look -up tables in the SCAQMD Final LST Methodology for a 5 -acre project in Source Receptor Area 17. The current look -up tables cover the years 2005 through 2007. The distance to the nearest receptors is 25 meters (80 feet), the closest distance available in the LST Methodology. The LSTs are summarized in Table 4.2 -8. Impact Analysis The onsite emissions during construction are compared with the localized significance thresholds and are summarized in Table 4.2 -8. The onsite emissions were generated by URBEMIS, with the exception that only onsite emissions are accounted for in the localized analysis. Onsite emissions are from fugitive dust during grading and off -road diesel emissions. As shown in Table 4.2 -8, unmitigated emissions during construction exceed the localized significance thresholds for NOx, PM,,, and PM2.s. Table 4.2.8: Localized Significance Analysis Onsite Emissions (pounds per day) Activity NO, co PM10 PM2.5 Demolition 7.6 4.8 21.6 4.9 Mass grading and excavation of material 71.9 31.4 26.9 8.1 Trenching 16.4 8.1 0.8 0.8 Building (2011) 318.3 98.1 10.0 9.2 Building (2012) 295.7 91.9 9.0 8.3 Building, Asphalt Paving, and Coating 323.4 109.0 11.5 10.6 Maximum Daily Emissions 323.4 109.0 26.9 10.6 4.2 -18 Michael Bmndman Associates H\Cl t(PN- JMb327b327W3MMVB270030 Sec 2AvQ ity.D