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HARBOR BLVD. MIXED USE TRANSIT CORRIDOR PLAN FINAL FIR <br />CITY OF SANTA ANA <br />5. Environmental Analysis <br />AIR QUALITY <br />The Initial Study, included as Appendix A, substantiates that impacts associated with the following threshold <br />would be less than significant: <br />■ Threshold AQ -5 <br />This impact will not be addressed in the following analysis. <br />5.2.2.1 SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT THRESHOLDS <br />The analysis of the proposed project's air quality impacts follows the guidance and methodologies <br />recommended in SCAQNID's CEQA Air Quaho Handbook and the significance thresholds on SCAQNID's <br />website.7 CEQA allows the significance criteria established by the applicable air quality management or air <br />pollution control district to be used to assess impacts of a project on air quality. SCAQMD has established <br />thresholds of significance for regional air quality emissions for construction activities and project operation. <br />In addition to the daily thresholds listed above, projects are also subject to the AAQS. These are addressed <br />though an analysis of localized CO impacts and localized significance thresholds (LSTs). <br />Regional Significance Thresholds <br />SCAQIVID has adopted regional construction and operational emissions thresholds to determine a project's <br />cumulative impact on air quality in the SoCAB. Table 5.2 -5 lists SCAQNID's regional significance thresholds. <br />Table 5.2 -5 SCAQMD Siqnificance Thresholds <br />Air Pollutant <br />Construction Phase <br />Operational Phase <br />Reactive Organic Gases (ROGsy Volatile <br />Organic Compounds (VOCs) <br />75lbs /day <br />55lbs /day <br />Carbon Monoxide (CO) <br />550lbs/day <br />550lbs/day <br />Nitrogen Oxides (NOx) <br />100lbs/day <br />55lbs /day <br />Sulfur Oxides (SOx) <br />150lbs/day <br />150lbs/day <br />Particulates (PMto) <br />150lbs/day <br />150lbs/day <br />Particulates (PM25) <br />55lbs /day <br />55lbs /day <br />Source: SCAQMD 2011. <br />CO Hot Spots <br />Areas of vehicle congestion have the potential to create pockets of CO called hot spots, which have the potential <br />to exceed the state one hour standard of 20 prim or the eight hour standard of 9 prim. Because CO is produced in <br />greatest quantities from vehicle combustion and does not readily disperse into the atmosphere, adherence to <br />ambient air quality standards is typically demonstrated through an analysis of localized CO concentrations. Hot <br />spots are typically produced at intersections, where traffic congestion is highest because vehicles queue for longer <br />periods and are subject to reduced speeds. Typically, for an intersection to exhibit a significant CO concentration, it <br />would operate at level of service (LOS) E or worse without improvements (Caltrans 1997). <br />7 SCAQMD's Au Quality Significance Thresholds are current as of March 2011 and can be found at <br />htq): //w .agmcigov /ceqa /hdbkhtml. <br />October 2014 Page 5.2 -13 <br />