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PARKING STRUCTURE OPERATIONAL IMPACTS <br />The proposed project would increase the number of parking spaces in proximity to off-site <br />residents from a 220 space surface parking lot to a 531 space parking structure. As a worst-case <br />for a local air quality impact analysis, it was assumed that every space was occupied and that <br />every vehicle arrives and departs in a single hour on a cold, damp, winter evening. The air <br />pollution exposure for the closest residents was evaluated in terms of CO and NOx using the <br />modeling output for LST analyses for the Central Orange County Source-Receptor Area (SRA). <br />At an average distance of 200 meters from the parking structure to the nearest homes, the <br />SCAQMDs LST guidance predicts a possible violation of CO or NO, standards for the following <br />hourly emission rates: <br />CO - 263.6 lb/hour may cause an exceedance <br />NO2 - 15.4 lbs/hour may cause an exceedance <br />The CO and NOx emitted by 531 cars arriving or departing within the same hour was calculated <br />by combining the travel distance within each level of the structure with the emission factor for a <br />travel speed of 5 mph. The travel distance was determined as follows: <br />Level # of Cars including Travel Distance Travel Miles <br />handicap spaces <br />One 114 325' 7 <br />Two 163 650' 20 <br />Three 160 975' 30 <br />Four 94 1,300' 23 <br />Total (Arrive or Depart) 80 <br />Total Arrive and Depart 160 miles <br />The EMFAC2011 (http://www.arb.ca.gov/nisei/niodeIin,.htm) computer model for California <br />automobiles in 2014 states that tailpipe emissions for light duty autos are as follows for running <br />and moving activities (output attached): <br />CO 2.65 grams/mile gas powered vehicle <br />0.93 grams/rnile diesel powered vehicle <br />NOx 0.19 grams/mile gas powered vehicle <br />0.77 grams/mile diesel powered vehicle <br />Although EMFAC2011 provides running emissions for light duty vehicles, idling emissions are <br />only calculated for medium and heavy duty trucks. However, the ARB provides the following <br />guidance for calculating idling emissions for light duty vehicles: