Seamless near-surface NO₂ concentration data over East-Central China during 2017-2023

Although nitrogen dioxide (NO₂) is a major threat to public health, traditional polar-orbiting satellites cannot resolve its strong diurnal variability because of their coarse revisit frequency. To overcome this limitation, we developed an hourly, gap-free NO₂ dataset for East-Central China for 2017–2023. Our method fuses geostationary observations with ground-based measurements and ancillary environmental data using a Random Forest framework with spatiotemporal optimization. The resulting concentrations agree well with in situ observations (sample-based validation: R² = 0.87, RMSE = 7.30 μg/m³; station-based validation: R² = 0.78, RMSE = 10.27 μg/m³) and maintain robust performance across all hours of the day. Here, we release the annual mean NO₂ concentration fields derived from this product.