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Air emissions were determined for the operation of the sand and gravel processing.The air <br /> emission calculations accounted for the proposed production levels (1,200 tons per hour and <br /> 4,000,000 tons per year),the number,types,and size of equipment, and the type of material <br /> processed and emission controls, if any. The emission factors were determined using the <br /> methodology found in Section 11.19.1 of EPA's AP-42. Table AQ-2 presents the emission <br /> factors for the sand and gravel processing operations. Additional emissions of toxic air pollutants <br /> such as formaldehyde, fluoranthane,naphthalane, and phenamthrane can occur as a result of dryer <br /> operations. <br /> Fugitive sources include the transfer of sand and aggregate,truck loading, mixer loading, vehicle <br /> traffic,and wind erosion from aggregate storage piles.The amount of fugitive emissions <br /> generated during the transfer of sand and aggregate depends primarily on the surface moisture <br /> content of these materials. <br /> TABLE AQ-2 <br /> EMISSION FACTORS FOR SAND AND GRAVEL PROCESSING <br /> PM10 NOx <br /> Emission Factor Emission Factor <br /> Emission Point (lbs/ton of material) (lbs/ton of material) <br /> Sand Dryer 2.0 0.031 <br /> Sand Dryer with Wet Scrubber 0.039 0.031 <br /> Sand Dryer with Fabric Filter 0.010 0.031 <br /> Sand Handling 0.0013 <br /> Sand Screening 0.0083 <br /> SOURCE:Compilation of Air Pollutant Emission Factors,AP-42,Fifth Edition,Volume 1:Stationary Point and Area ' <br /> Sources,Section 11.19.1 Sand and Gravel Processing,November 1995. <br /> Concrete Batching Operations <br /> Concrete is composed essentially of water,cement, sand (fine aggregate), and coarse aggregate, <br /> consisting of crushed stone. Sand, aggregate, cement,and water are all gravity fed from a weigh <br /> hopper into the mixer trucks. The cement is transferred to elevated storage silos. The sand and <br /> coarse aggregate are transferred to elevated bins. From these elevated bins, the constituents are <br /> fed by gravity or screw conveyor to weigh hoppers, which combine the proper amounts of each <br /> material. <br /> Air emissions were determined for the operation of the concrete batching plants.The air emission <br /> calculations accounted for the proposed production level,the number,types, and size of <br />