Item 28 - Public Hearing - ZOA No. 20204-01 South Coast Technology Center

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South Coast Technology Center Project CEQA Exemption 15183 Table 4.3-4 Localized Significance of Operational Emissions Emissions Source Emissions (pounds per day) NOx CO PM10 PM2.5 Maximum Daily Area Source Emissions 0.12 14.10 0.03 0.02 Maximum Daily On -Site Mobile Emissions' 5.48 6.78 2.94 0.82 Maximum Daily Energy Emissions 0.00 0.00 0.00 0.00 Total Maximum Daily On -Site Operational Emissions 5.60 20.88 2.97 0.84 Localized Significance Threshold2 183 1,253 3 2 Thresholds Exceeded? No No No No Notes: 1. As it was conservatively assumed that approximately 20 percent of the project's mobile trips would occur on the 15.8-acre site, the operational LST assessment analyzed 20 percent of the maximum daily winter or summer operational mobile emissions. 2. The Localized Significance Threshold Mass Rate Screening Criteria was determined using Appendix C of the SCAQMD Final Localized Significant Threshold Methodology guidance document for pollutants NOx, CO, PM10, and PM2.5. The Localized Significance Threshold was based on the site acreage (approximately 15.8 acres; therefore, the five -acre thresholds were used as a conservative analysis) and Source Receptor Area 17, Central Orange County. Source: Refer to Appendix A of Attachment A, Air Quality Assessment, for CalEEMod outputs and assumptions used in this analysis. Carbon Monoxide Hotspots CO emissions are a function of vehicle idling time, meteorological conditions and traffic flow. Under certain extreme meteorological conditions, CO concentrations near a congested roadway or intersection may reach unhealthy levels (i.e., adversely affect residents, school children, hospital patients, the elderly, etc.). To identify CO hotspots, the SCAQMD requires a CO microscale hotspot analysis when a project increases the volume -to -capacity ratio (also called the intersection capacity utilization) by 0.02 (two percent) for any intersection with an existing level of service (LOS) D or worse. Because traffic congestion is highest at intersections where vehicles queue and are subject to reduced speeds, these hot spots are typically produced at intersection locations. The Basin is designated as an attainment area for state and federal CO standards. There has been a decline in CO emissions even though vehicle miles traveled (VMT) on U.S. urban and rural roads have increased. On -road mobile source CO emissions have declined 24 percent between 1989 and 1998, despite a 23 percent rise in motor VMT over the same 10 years. California trends have been consistent with national trends; CO emissions declined 20 percent in California from 1985 through 1997, while VMT increased 18 percent in the 1990s. Three major control programs have contributed to the reduced per -vehicle CO emissions: exhaust standards, cleaner burning fuels, and motor vehicle inspection/maintenance programs. A detailed CO analysis was conducted in the Federal Attainment Plan for Carbon Monoxide (CO Plan) for the SCAQMD's 2003 Air Quality Management Plan. The locations selected for microscale modeling in the CO Plan are worst -case intersections in the Basin and would likely experience the highest CO concentrations. Of these locations, the Wilshire Boulevard/Veteran Avenue intersection experienced the highest CO concentration (4.6 parts per million (ppm)), which is well below the 35-ppm 1-hr CO federal standard. The Wilshire Boulevard/Veteran Avenue intersection is one of the most congested intersections in southern California with an average daily traffic (ADT) volume of approximately 100,000 vehicles per day. As the CO hotspots were not experienced at the Wilshire Boulevard/Veteran Avenue intersection (100,000 ADT), it July 2024 Page 30