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TABLE AQ-7 EMISSION FACTORS (2021) FOR NONROAD EQUIPMENT AND MOTOR VEHICLES - Equipment Type Units ROG CO NOx SO2 PM10 Excavator g/hp-hr 0.07 0.44 0.93 0.38 0.10 Haul Trucks(onsite) g/hp-hr 0.10 0.82 1.55 0.64 0.16 Front End Loader g/bp-hr 0.14 1.39 0.91 0.29 0.19 Dozer g/hp-hr 0.10 0.82 1.58 0.64 0.16 Grader g/hp-hr 0.10 0.82 1.58 0.64 0.16 J Water Pull g/hp-hr 0.10 0.82 1.55 0.64 0.16 Bobcat Loader g/hp-hr 0.10 0.84 1.65 0.64 0.16 J Maintenance Trucks g/hp-hr 0.10 0.82 1.55 0.64 0..16 Lube&Fuel Truck g/hp-hr 0.10 0.82 1.55 0.64 0.16 Forklift g/bp-hr 0.12 2.30 1.90 0.71 0.32 Pickup Trucks(onsite) g/mile 0.051 1.658 0.211 0.004 0.040 Haul Trucks(offsite) g/mile 0.266 1.614 2.020 0.017 0.143 SOURCE: California Air Resource Board.2002.EMFAC2002 Version 2.2 and Environmental Protection Agency. 1991.Nonroad Engine and Vehicle Emission Study. Dispersion Modeling Dispersion is the process by which atmospheric pollutants disseminate due to wind and vertical stability. The results of a dispersion analysis are used to access pollutant concentrations at or near an emission source. The results of an analysis allow a direct comparison of predicted concentrations of pollutants to air quality or exposure standards. A rising pollutant plume reacts with the environment in several ways before it levels off. First, the plume's own turbulence interacts with atmospheric turbulence to entrain ambient air. This mixing process reduces and eventually eliminates the density and momentum differences that cause the plume to rise. Second,the wind transports the plume during its rise and entrainment process. Higher winds mix the plume more rapidly, resulting in a lower final rise. Third,the plume interacts with the vertical temperature stratification of the atmosphere, rising as a result of buoyancy in the unstable-to-neutrally stratified mixed layer. However,after the plume encounters the mixing lid and the stably stratified air above, its vertical motion is dampened.