Background pollution data for the UK is updated every year using the latest measurement data from the various networks around the UK.
For example, when considering ammonia we use measurement data from the Ammonia Network and then produce yearly pollutant maps (5km) which are outputted by the CBED model. This is done through a kriging methodology/interpolation. To help with the spatial distribution of ammonia we run our national transport model (FRAME) which gives us a spatial pattern of the ammonia concentrations which are ‘calibrated’ relative to annual ammonia measurements. This provides the local scale variability that cannot be derived from the network measurement data on their own. More information about CBED is available here.