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SANTA ANA REZONE PROJECT <br />INITIAL STUDY/MITIGATED NEGATIVE DECLARATION <br />Quality Standards (CAAQS). To minimize efforts, the SCAQMD developed mass rate lookup tables as <br />a simple screening procedure. If a project's on -site emissions do not exceed the screening levels for <br />any pollutant, it can be concluded that the project would not cause or contribute to an adverse <br />localized air quality impact. Screening levels are provided for various distances (i.e., 82 feet [25 <br />meters], 164 feet [50 meters], 328 feet [100 meters], 656 feet [200 meters], and 1,640 feet [500 <br />meters]) between the project boundary and the nearest sensitive receptor and various project site <br />acreages (i.e., 1, 2, and 5 acres). As discussed above, the closest sensitive receptors are 160 feet, or <br />approximately 50 meters, south of the project site. <br />The LST Methodology only applies to on -site emissions and states that "off -site mobile emissions <br />from the project should not be included in the emissions compared to LSTs." However, if a project's <br />overall emissions (i.e., including off -site mobile emissions) are below the LSTs, then the proposed <br />project's on -site impacts would also fall below the LSTs. For streamlined yet conservative analysis <br />purposes, and given the proposed project's minimal construction and operation emissions, the <br />proposed project's overall emissions are compared to the LSTs. <br />Localized Construction Analysis <br />Although the project site is 3.43 acres, the proposed project would only actively disturb fewer acres a <br />day during construction phases. Therefore, the LST screening thresholds for 1 acre were utilized for <br />the LST analysis, which are the most stringent screening thresholds. The LSTs have been obtained <br />from the LST Methodology for 1-acre project sites located in Source Receptor Area 17, Central <br />Orange County. <br />Table 3 presents the proposed project's maximum daily on -site emissions compared with the <br />applicable LSTs. <br />Table 3: Construction Localized Significance Screening Analysis <br />Activity <br />Maximum Daily Construction Emissions <br />Localized Significance Thresholds <br />(SRA 17, 1-acre site, 50 meter distance to receptor) <br />Exceeds Threshold? <br />On -site Emissions (pounds per day) <br />NOx CO PM10 PM2.5 <br />29.69 <br />23.61 <br />8.76 <br />2.33 <br />83 <br />173 <br />12 <br />4 <br />No <br />No <br />No <br />No <br />Notes: <br />NOx = oxides of nitrogen <br />CO = carbon monoxide <br />PM10 = particulate matter less than 10 microns in diameter <br />PM2.5 = particulate matter less than 2.5 microns in diameter <br />SRA = State Responsibility Area <br />Source of emissions: Appendix A. <br />Source of thresholds: SCAQMD Mass Rate Lookup Tables for 1-acre site in Source Receptor Area 17 for sensitive receptors <br />located 50 meters from the project site. <br />FCS 33 <br />Https://adecinnovations.sharepoint.com/sites/PubiicationsSite/Shared Documents/Publications/Client(PN-JN)/D327/03270D47/ISMND/0327D047 Santa Ana Rezone Project ISMND.docx <br />