North West London Air Pollution Exposure Estimates

Modelled concentrations (µg/m3) of annual average nitrogen dioxide (NO2) and particulate matter with diameter <2.5µm (PM2.5) were linked to postcode centroids in Greater London. Air pollution exposure estimates (i.e. concentrations) were derived using models developed for the year 2015 by overlaying the x,y location of postcode centroids with NO2 and PM2.5 maps (25m x 25m resolution) within a geographic information system (GIS). Following analysis of changes in air pollution measurements over time, using routine monitoring data from the DEFRA-run Automatic Urban and Rural Network (AURN), we made adjustments to the 2015 modelled concentrations to estimate 2010 to 2019 exposures using a method know as ‘differencing’ (Gulliver et al. 2013).