Less than Significant with Mitigation Incorporated. Potential short-term impacts may occur from equipment exhaust emissions and particulate materials (dust) generated during excavation and grading. As noted above, the combined air quality construction impacts would be generated over a roughly 7.5 month (226 days) period, plus other emissions generated over the same period by operation of the diesel-powered equipment and commuting to the site by six to twelve workers. It is assumed that Phase 1 and 2 construction impacts will not occur during the same year, since Phase 2 is dependent on the biological success of Phase 1. Grading for Phase 1 would involve approximately 247,000 cubic years of cut and fill. Phase 1 by itself may not balance and could need to export up to approximately 22,600 cubic yards of soils to Phase 2. Phase 2 of the project would use roughly the same amount of employees and equipment, but construction would take a little longer, about 125 days. Grading for Phase 2 would involve an additional approximately 233,000 cubic years of balanced cut and fill. Air emissions generated by heavy equipment operation, and employee commuting, for each of the two phases is expected to be below the thresholds set by the YSAQMD, and will not contribute significantly to local violations of regulatory standards. However, grading could produce particulate matter (PM) emissions in excess of YSAQMD standards. A calculation of potential PM10 emissions was prepared according to methodology outlined in U.S. Environmental Protection Agency and California South Coast Air Quality Management District guides (USEPA, 1999; CSCAQMD, 1996; WRAP, 2006). Factors of 0.011 ton/month plus 0.059 ton/1,000 cubic yards for on-site cut/fill and 0.22 ton/1,000 cubic yards for off-site cut/fill were used from the project description. The projected amount of grading for Phase 1 of 137 acres is estimated to generate 24.36 tons of PM10 emissions, below the YSAQMD threshold standard of 80 pounds per day. The projected amount of grading for Phase 2 of 183 acres is estimated to generate 22.00 tons of PM10 emissions, also below the YSAQMD threshold standard of 80 pounds per day The following standard measures to reduce construction dust and construction equipment emissions are recommended by the YSAQMD and will ensure that potential impacts remain at a less than significant level: Mitigation Measure AQ-1:
Less than Significant with Mitigation Incorporated. A noise analyses for the project was prepared by Xxxxxx Xxxxx Associates and is included as Appendix E. The study includes onsite noise monitoring, noise projections for construction activities and construction traffic, and noise projections from project-related traffic at buildout. Noise Standards All noise-generated onsite is subject to the City’s Noise Ordinance (Chapter 8.2) and the Land Use Compatibility Guidelines issued by the California Department of Health Services. The California Noise Insulation Standards (Title 25 of the California Code of Regulations) uses CNEL as its primary noise rating method. An interior CNEL of 45 dBA is mandated for multiple family dwellings in Title 24 of the California Code of Regulations, and is also considered the desirable noise exposure for single family dwelling units. A 45 dBA interior standard with conventional construction usually equates to a 65 CNEL exterior standard. The Land Use Compatibility Guidelines (Exhibit 6 in Appendix E) indicate new construction or development may proceed if detailed noise analyses identifying noise reduction requirements is completed for low-density single family homes in areas with projected noise levels of 65 to 75 Community Equivalent Noise Levels (CNEL). The CNEL takes average sound levels at an observation point and adds a weighting penalty to those sounds that occur during the evening and night hours. A penalty of 5 dBA is added between 7 pm and 10 pm, and a 10-dBA penalty is added between 10 pm and 7 am. CNEL noise levels are often reported as 65 dB CNEL or 65 CNEL. The City of Brea Noise Ordinance (Chapter 8.20 of the Municipal Code) controls excessive noise from stationary (non-transportation) noise sources only. Noise ordinance requirements do not apply to mobile noise sources on public roadways, construction demolition and other construction activities. The Noise Ordinance establishes exterior and interior noise standards for the generation of noise from an onsite land use (i.e. the generation source) to another offsite sensitive land use (i.e. the receiving land use) only. The Ordinance does not apply to noise impacts within a project site. Therefore, the Ordinance is applicable to offsite land uses surrounding the project. The Noise Ordinance (Chapter 8.20: Noise Control) applies 55 dBA L50 daytime (7 am to 10 pm) and 50 dB L50 nighttime (10 pm to 7 am) as the standard for fixed (stationary) noise sources within the City. This means that a fixed noise source cannot ca...
Less than Significant with Mitigation Incorporated. The project will not cause substantial adverse effects on human beings. Implementation of the approved OCHA approved Remedial Action Plan will ensure all contaminated soil onsite is removed without any substantial adverse effects on adjacent residents, construction employees or the general public. The project must also comply with soil gas assessment, and if needed, any additional OCHA requirements needed to comply with the RAP. As indicated in Section 8, the project shall comply with the following mitigation measure. Mitigation Measure
Less than Significant with Mitigation Incorporated. Less Than Significant
