Impacts of Hypothetical NOx Sources on Ozone Formation in East Tennessee

Ahmed, Mamun

ABSTRACT: This thesis studied the effects of hypothetical NOx sources located in East Tennessee on the tropospheric ozone concentrations impacting the Great Smoky Mountains National Park (GSMNP) using the Urban Airshed Model (UAM). The product of this study is a technique of assessing the potential impact of a new or modified large NOx source on ozone concentrations within a Class I area, which includes an up-to-date detailed emissions inventory. The East Tennessee Modeling Domain (ETMD) consists of 94 counties in six different states with an area of 75,900 km2: Tennessee (40), North Carolina (22), South Carolina (8), Georgia (17), Kentucky (4), and Virginia (3). The emissions, including point, area, mobile (on and non-road), and biogenic sources were chemically, temporally, and spatially allocated throughout the domain. The four hypothetical NOx source locations selected to be studied in ETMD were: Knoxville, Crossville, Cleveland, and the Tri-Cities airport (Bristol, Kingsport, and Johnson City) area. The days to be modeled by the UAM for each source location were July 07 and 10 (Knoxville), June 30 (Crossville), June 14 (Cleveland), and July 25 (Tri-Cities airport) of 1990. The study compares the predicted incremental ozone concentrations in the GSMNP due to the detailed emissions inventories with those modeled by constant emissions densities used in previous study. The results are also compared to those obtained from a screening technique which used the Mapping Areawide Predictions of Ozone model (MAP-03). The MAP-03 predicted an average of about 3 times higher incremental ozone concentrations in the GSMNP than the UAM simulations using detailed emissions inventories.