Sulphur and nitrogen atmospheric Concentration Based Estimated Deposition (CBED) data for the UK, 2018-2020

The Concentration Based Estimated Deposition (CBED) methodology generates maps of wet and dry deposition of sulphur, oxidised and reduced nitrogen, and base cations from measured concentrations of gases and particulate matter in air and measured concentrations of ions in precipitation. These data are collected at sites in the UK Eutrophying and Acidifying Pollutants (UKEAP) network. The site-based measurements are first interpolated to generate maps of concentrations for the UK. The ion concentrations in precipitation are combined with an annual precipitation map from the UK Meteorological Office to generate values of wet deposition. Gas and particulate matter concentration maps are combined with spatially distributed estimates of habitat-specific deposition velocities to generate dry deposition for 5 land cover categories: forest, moorland, grassland, arable and urban. The deposition to the 5 land cover categories are combined, depending on the relative proportions of different land cover categories in the grid square, to generate values for grid square averaged deposition. Dry deposition includes deposition of gases (Sulphur Dioxide (SO2), Nitric Acid (HNO3), Nitrogen Dioxide (NO2) and Ammonia (NH3) and particulate matter (sulphate, nitrate, ammonium, calcium and magnesium) to vegetation. For critical load exceedance calculations, deposition values for moorland are applied to all non-woodland habitats, and deposition values for forest are applied to all woodland habitats.

Data processing was done using the R programme and results output as CSV files. These were then transformed in a suitable format for ingestion into the Environmental Information Data Centre.