Daily 1 km Fine Particles (PM2.5) Concentrations across the United Kingdom, 1980-2019

This dataset contains daily PM2.5 concentrations (μg/m3) across the United Kingdom at 1 km × 1 km spatial resolution. A two-stage model was developed to reconstruct long-term spatiotemporal variations in PM2.5 levels from 1980 to 2019. In stage 1, co-located PM10 measurements were used to augment PM2.5 observations through a calibration model. In Stage 2, the LightGBM algorithm integrated both observed and augmented PM2.5 values with multi-source predictors to back extrapolate historical concentrations. The model achieved strong predictive performance during 2010–2019 (grid-based cross-validation R2 = 0.71–0.85) and reasonable back-extrapolation accuracy for 1998–2009 (independent testing R2 = 0.32–0.65) at the daily level. Pollution episodes in the 1980s and pollution levels in the 1990s were also effectively reproduced.