We developed a high-resolution land–atmosphere modelling system for urban CO₂ emissions over the LA Basin. We evaluated various model configurations, FFCO₂ products, and the impact of the model resolution. FFCO₂ emissions outpace the atmospheric model resolution to represent the CO₂ concentration variability across the basin. A novel forward model approach is presented to evaluate the surface measurement network, reinforcing the importance of using high-resolution emission products.