Assessment of Airport-Related Emissions and Their Impact on Air Quality in Atlanta, GA, Using CMAQ and TROPOMI.

Impacts of emissions from the Atlanta Hartsfield-Jackson Airport (ATL) on ozone (O 3 ), ultrafine particulates (UFPs), and fine particulate matter (PM 2.5 ) are evaluated using the Community Multiscale Air Quality (CMAQ) model and high-resolution satellite observations of NO 2 vertical column densities (VCDs) from TROPOMI. Two airport inventories are compared: an inventory using emissions where landing and take-off (LTO) processes are allocated to the surface (default) and a modified (3D) inventory that has LTO and cruise emissions vertically and horizontally distributed, accounting for aircraft climb and descend rates. The 3D scenario showed reduced bias and error between CMAQ and TROPOMI VCDs compared to the default scenario [i.e., normalized mean bias: -43%/-46% and root mean square error: 1.12/1.21 (1015 molecules/cm 2 )]. Close agreement of TROPOMI-derived observations to modeled NO 2 VCDs from two power plants with continuous emissions monitors was found. The net effect of aviation-related emissions was an increase in UFP (j mode in CMAQ), PM 2.5 (i + j mode), and O 3 concentrations by up to 6.5 × 10 2 particles/cm 3 (∼38%), 0.7 μg/m 3 (∼8%), and 2.7 ppb (∼4%), respectively. Overall, the results show (1) that the spatial allocation of airport emissions has notable effects on air quality modeling results and will be of further importance as airports become a larger part of the total urban emissions and (2) the applicability of high-resolution satellite retrievals to better understand emissions from facilities such as airports.