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In general,the transport and concentration of pollutants from vehicular sources are influenced by three principal meteorological factors: wind direction, wind speed, and atmospheric stability, which accounts for the effects of dispersion or mixing in the atmosphere. Wind direction, which influences the accumulation of pollutants at a particular receptor location, was chosen to maximize pollutant concentrations at the receptor. In applying the CALINE4 modeling, the wind angle was varied to determine the worst-case wind direction resulting in the maximum concentrations. For short-term average impacts,computations was performed using a wind speed of 1 meter/second, stability class F"very stable",representing a worst case assumption of conditions and an aerodynamic roughness coefficient of 400 cm,typical of the environment surrounding the Proposed Project. EPA's SCREEN3 model(Version 96043) was used for the screening modeling analysis.The _ SCREEN3 model is an appropriate model for this analysis based on the coverage of simple and complex terrain. It also predicts 1-hour maximum concentrations and can predict 24-hour average concentrations in the complex terrain mode. The SCREEN3 model was executed using the regulatory default options(stack-tip downwash, buoyancy induced dispersion,final plume rise),default wind speed profile categories, default potential temperature gradients, no pollutant decay,using rural dispersion coefficients. Receptors were located at residences nearest existing and project operations accounting for typical annual average operations. The full meteorology option was used in the modeling analysis. SCREEN3 examines a range of stability classes and wind speeds to identify the worst- case meteorological conditions. The ambient temperature was assumed to be 68 degrees F(293 K). Emission sources were based on typical annual equipment usage of those type of equipment with the worst case daily emission rates. The SCREEN3 model was used to calculate 1-hour concentrations. Maximum concentrations for an annual averaging time were determined by multiplying the 1-hour maximum impacts by a 1 conversion factor of 0.1. The incremental health risk was determined by addressing the difference between the annual concentration during the existing and project conditions. The SJVQMD has a significance threshold for health risk exposure to diesel emissions of 10 cancers per million for 70-year exposure. Accordingly, the SJ VAQMD CEQA Guidelines indicate the primary concern from diesel engine exhaust emissions is a potential long-term health risk to sensitive receptors. Receptors were placed at distances of 1090, 1190, and 1500 meters from the source(designated as the center of the Project site). Annualized average emissions from 2007 and 2021 from onsite equipment were determined. A generalized emission area source with dimensions of 300 by 300 meters with a height of 5 meters was used. Rural dispersion coefficients were used. A Y