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MacArthur Project Modification -- Santa Ana - Air Quality Assessment <br />KPC Environmental, Inc., <br />The analysis for the proposed project assumed a schedule for the construction and <br />estimated the project completion in 12-months. Increasing the construction timeline <br />would allow for each task in the construction of the buildings to be completed over a <br />greater timeline which in some cases such as grading/excavation and coatings would <br />decrease the estimated emissions presented in this analysis. This analysis is presenting a <br />"worst-case" construction scenario using a compressed construction schedule to present <br />the construction emissions at the highest anticipated levels. <br />5.1.1 Mass Grading/Parking Structure Excavation Emissions <br />The proposed project site will require mass grading/excavation to prepare the site for <br />construction. Mass Grading estimates in this assessment are based on a default <br />URBEMIS scenario with PM10 levels at 20 lbs/acre/day utilizing 5-pieces of heavy <br />equipment including 2-excavators, 1-grader, 1 rubber tired dozer, 1 <br />tractors/loaders/backhoes, and 1-other (ICE) equipment over a period of approximately <br />40 active work days. Estimated emissions during grading/excavation included export of <br />approximately 200,000 cubic yards of soil from the excavation using 20-cubic yard dump <br />trucks traveling 1,000 vehicle miles per day. <br />Mitigation measure (Best Management Practice) of watering site 2-times per day was <br />used for PM10 & PM2.5. No mitigation or BMP's were used in the URBEMIS model for <br />other emissions constituents. <br />Table 5-1 Mass Gradin2/Excavation <br />Pollutant Unmitigated <br />(lbs/day) Mitigated <br />(lbs/day) SCAQMD <br />Threshold <br />ROG 8.36 8.36 75 <br />NOx 78.53 78.53 100 <br />CO 40.07 40.07 550 <br />PM 10 23.89 15.20 150 <br />S02 0.04 0.04 150 <br />PM 2.5 7.66 5.85 55 <br />CO2 9.797.61 9.797.61 N/A <br />void-underline indicates exceedance of SCAQMD Threshold. <br />02/02/11 <br />13 <br />75B-121