Modeling Coastal-Urban Impacts on Air Quality Distribution in New York City: Evaluation Based on High-Spatial-Resolution NO2 Retrievals

Coastal cities face critical challenges in managing ozone pollution due to their high population density and complex interactions between urbanization and coastal meteorology. This study uses New York City (NYC) as a case study to investigate how urban surfaces influence heatwaves, land-sea breezes, and planetary boundary layer dynamics, and how these factors shape nitrogen dioxide (NO₂) distribution and ozone formation. Using data from the 2018 Long Island Sound Tropospheric Ozone Study (LISTOS), we leverage an airborne high-spatial-resolution ultraviolet-visible spectrometer to measure NO₂ tropospheric column densities. These observations provide valuable insights into precursor dynamics and serve as a benchmark for evaluating the performance of the urban Weather Research and Forecasting model coupled with Chemistry (uWRF-Chem), which simulates interactions between urban meteorology and chemical transport. Our findings highlight key features of chemical dynamics in NYC during a high ozone and heatwave episode. Early morning urban heat island effects trigger sea-breeze fronts, concentrating ozone precursors in the city center. Building-induced drag reduces wind flow, altering advection patterns and prolonging the residence time of these precursors over the urban area. These processes ultimately result in elevated ozone levels both within the city center and in downwind regions. Together, these insights enhance our understanding of urban air quality challenges and provide a foundation for more effective pollution mitigation strategies in densely populated coastal cities.