“…A MACCS polar-coordinate, compass-sector, population distribution centered on Buxton was constructed using SECPOP90 (Humphreys et al 1997). This population distribution had ten downwind distance intervals which had the following outer radii: 1.6, 3.2, 4.8, 6.4, 8.0, 16, 32,48, 64, and 80 km.…”