Abstract

In January of 2020, the power plant located in Lake Julian, North Carolina, transitioned from coal to a combined- cycle natural gas power plant. Given the respective decrease in emissions associated with natural gas electricity generation as compared to coal, one can assume that the air quality in western North Carolina, where the power plant is located, was likely impacted by this transition. We examined this change in air quality using CAMx v7.10, a regional chemical transport model. Two scenarios were simulated, one with the inclusion of the coal-fired power plant (basecase), and another with the powerplant removed from the simulation (zeroout). We estimated the power plant's impact on air quality by analyzing the difference between these two scenarios. Three major pollutants were analyzed: ozone (O3), NOx, and fine-scale particulate matter (PM2.5). Three species of PM2.5 were also analyzed: SO4, NO3, and NH4. Results show a calculable positive difference between the basecase and the zeroout scenarios for ozone, NOx, and PM2.5, meaning that the basecase scenario had larger pollutant concentrations than the zeroout scenario. There is a 1-hr maximum difference of up to 2.5 ppb for ozone, up to 2.0 ppb for NOx, and up to 0.9 ?g/m3 for PM2.5. We have also found that the ozone difference is largest during ozone season, as compared to the annual values. Maximum differences for all three pollutants occur within 24km from the powerplant.

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