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 4.3-3 Localized Significance of Construction Emissions Emissions Source Emissions (pounds per day) NOx CO PM10 PM2.5 Maximum Daily Construction Emissions', 2 45.50 43.30 4.34 2.74 LST Screening Thresholc13 115 715 6 4 Thresholds Exceeded? No No No No Notes: 1. The grading phase would overlap with the building construction phase during Year 1; maximum daily construction emissions from these two phases are combined to be presented as the worst -case scenario for NOx, CO, PM10, and PM2.5 emissions. 2. Modeling assumptions include compliance with SCAQMD Rule 403 which requires the following: properly maintain mobile and other construction equipment; replace ground cover in disturbed areas quickly; water exposed surfaces three times daily; cover stockpiles with tarps; water all haul roads twice daily; and limit speeds on unpaved roads to 15 miles per hour. 3. 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 anticipated daily acreage disturbance for construction (approximately three acres; therefore, the two -acre thresholds were used) 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. Asbestos Asbestos is a term used for several types of naturally occurring fibrous minerals that are a human health hazard when airborne. The most common type of asbestos is chrysotile, but other types such as tremolite and actinolite are also found in California. Asbestos is classified as a known human carcinogen by state, federal, and international agencies and was identified as a toxic air contaminant by CARB in 1986. Asbestos can be released from serpentinite and ultramafic rocks when the rock is broken or crushed. At the point of release, the asbestos fibers may become airborne, causing air quality and human health hazards. These rocks have been commonly used for unpaved gravel roads, landscaping, fill projects, and other improvement projects in some localities. Asbestos may be released to the atmosphere due to vehicular traffic on unpaved roads, during grading for development projects, and at quarry operations. All of these activities may have the effect of releasing potentially harmful asbestos into the air. Natural weathering and erosion processes can act on asbestos bearing rock and make it easier for asbestos fibers to become airborne if such rock is disturbed. According to the Department of Conservation Division of Mines and Geology, A General Location Guide for Ultramafic Rocks in California — Areas More Likely to Contain Naturally Occurring Asbestos Report, serpentinite and ultramafic rocks are not known to occur within the Project area." According to the Attachment C, Cultural and Paleontological Resources Identification Memorandum, the existing buildings were built after the 1980s. Thus, the buildings are not likely to contain asbestos. However, SCAQMD Rule 1403 requires that, prior to the start of demolition activities, the existing structure shall be thoroughly surveyed for the presence of asbestos by a person that is certified by Cal/OSHA for asbestos surveys. Rule 1403 requires that the SCAQMD be notified a minimum of 10 days before any demolition activities begin with specific details of all asbestos to be removed, start and completion dates of demolition, work practices and engineering 11 California Department of Conservation Division of Mines and Geology, A General Location Guide for Ultramafic Rocks in California — Areas More Likely to Contain Naturally Occurring Asbestos Report, August 2000, https://ww3.arb.ca.gov/toxics/asbestos/ofr 2000-019.pdf, accessed April 3, 2024. July 2024 Page 28