75D - PH- MAIN PLACE TRANSFORMATION

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standards may not be exceeded more than I day per year, and both annual standards may not be exceeded at all. Both the annual and 24-hour state PMI O standards have been violated several times during the last four years in the project region (ARB 1994, 1993, 1992, 1991). Attainment Status and Air Quality Planning The project region, located in the Orange County portion of the South Coast Air Basin (SCAB), is classified as a nonattainrnent area for the state and federal CO standards, an extreme nonattaimnent area for the state and federal ozone standards and a nonattainment area for the state and federal PMIO standards (Chico, personal communication, March 26, 1996). The South Coast Air Quality Management District (SCAQMD) is responsible for monitoring air quality and enforcing air quality regulations in the Orange County portion of the SCAB. In 1994, the SCAQMD prepared an air quality attainment plan (AQMP) for the SCAB which included the project region. The ozone portion of this plan forms the ozone SIP for the SCAB. Additionally, the SCAQMD is revising the 1994 AQMP and the revised version is due to ARB in 1997. The PMIO portion of this revised plan, which will later become the PMIO SIP, is due to EPA in February 1997 (Hogo, personal communication, October 27, 1996). Impacts Calculation of Construction Emissions Three sources of construction -related emissions are assessed in this analysis: construction worker vehicles, construction trucks, and construction equipment. Emissions of CO, ROO, NOx, and PMIO generated by construction workers commuting to the project site were estimated by multiplying the maximum number of construction worker trips expected to be made per day times the average trip length and an emission rate for each pollutant. Emission rates were generated using EMFAC7F, release 1.1, a program created by ARB to estimate vehicle emission rates. The maximum number of trips expected to be made during any day of construction was used to ensure that this would be a worst -case analysis. Construction truck emissions were calculated similarly. Exhaust emissions generated by the operation of construction equipment were estimated by multiplying the maximum number of hours of operation of each type of equipment expected to be used on the busiest day of construction by an emission rate for each pollutant. Emission rates for the various types of construction equipment were taken from the document "Compilation of Air Pollutant Emission Factors" (EPA 1985). This document contains emission rates for a broad range of pollutant -producing equipment and activities. The maximum number of pieces of equipment and maximum number of hours of equipment operation expected to occur during project construction was used to ensure that this would be a worst -case analysis. Addendum E1Rfor Maln P acel&nta Ana (ER96.033) - _ - Apri14. 1996 Page 19 Project No. 96.066 75D-410