Coastal urban environments face unique challenges associated with air quality-meteorology interactions. In this study, high resolution chemical transport modeling over the Greater Boston area was performed to improve our understanding of sea breezes impacts on the spatiotemporal variability of primary and secondary pollutants. We perform WRF-Chem simulations at 3 km resolution over June 22 to 10 July 2019 (a period that included 10 sea breeze occurrences), and use Pandora tropospheric NO2 column, surface air quality monitoring, and vertical meteorological aircraft profiles for evaluation. The model generally reproduces observed spatiotemporal variability of air pollution during sea breezes well. Tropospheric columns of NO2 predicted by the model and observed by the Pandora instrument show that sea breezes are associated with rapid increases and steep gradients in tropospheric NO2 and confirm accumulation of local primary emissions. Spatial heterogeneity in tropospheric NO2 is strongly governed by inland penetration lengths of the sea breeze front. Process diagnostics show that three sea-breeze days where O3 observations recorded hourly concentrations >70 ppb have both efficient net chemical O3 production in the boundary layer (>10 ppb/hr) and rapid O3 convergence in the near-surface convergence zone (>20 ppb/hr). During sea breezes, interactions between photochemistry, the convergence zone inland penetration, and urban NOx titration effects, contribute to strong heterogeneity and high O3 inland that is not captured by the current monitoring network. We discuss monitoring needs and model applications for the sea breeze scenarios, with broad implications for air quality monitoring in coastal urban environments. Plain Language Summary The sea breeze is a local meteorological system that brings air from the sea over the land during the day. In areas that usually experience offshore winds, this means the system can recirculate early morning pollutant emissions back onshore later in the day. Understanding the behavior of air pollutants in coastal urban environments is essential for air quality management, but land-sea breeze circulations are characterized by fine scale features and rapid changes in pollution levels that pose challenges for traditional monitoring and satellite retrievals. In the Greater Boston area, we use highly resolved information from a regional chemical transport model combined with observational assets to examine pollutant behavior and model performance. We find new evidence of underestimated regional ozone pollution and nitrogen dioxide column spatial variability associated with sea breezes. This variability is governed by how far the sea breeze penetrates inland, but is also affected by interactions between chemistry and atmospheric dynamic that are not well captured by current monitoring and coarse resolution models. Our results provide valuable insights for future ground-based and satellite remote sensing monitoring, highlighting that customized strategies for monitoring coastal urban air quality are required from high-resolution models constrained by carefully allocated observations.