Fig. 1: The maps display PM2.5 levels on a specific day over Great Britain, with three locations (large black dots) that represent the residential addresses of a specific subject (ID 2 in Table 1).

The magnified area on top represents the exact location at higher resolution, surrounded by the four nearest centroids (small indigo dots) of the overlaid PM2.5 grid. Without interpolation, the residential exposure value (small black dot) would be represented by the value of the nearest centroid. The magnified area below illustrates the process of reconstructing the residential value as a bilinear interpolation of the four nearest centroids.