In this project we used fine spatial resolution nitrogen dioxide (NO2) information (250 × 560 m 2 ) from the Geostationary Coastal and air pollution events Airborne Simulator (GCAS) instrument , available during the September 2021 NASA/TCEQ Tracking Aerosol Convection ExpeRiment -Air Quality (TRACER-AQ) field campaign , to better understand the fine-scale structure of NOx emissions in the Houston metropolitan area including a sector-by-sector analysis. Complementing the airborne observations, we perform a simulation using the Comprehensive Air Quality Model with Extensions (CAMx) at fine spatial resolution (444 × 444 m 2 ). The model output has already been compared to data from GCAS and TROPOMI in a complementary paper . In this project, we push further by using source-tagged NO2 information from CAMx and GCAS data to estimate more accurate contributions from different NOx emission sectors. We do this by using flux divergence methods on the GCAS data and by training a multiple linear regression model to the airborne retrievals, with the CAMx source-tagged NO2 as the independent variables.