Air pollution population exposure evaluation in the Vaal Triangle using GIS

M.Sc.The evaluation of population exposure to air pollution is a fundamental reason for management and control of regional air quality. The purpose of this study was to determine the exposure of the local population to PM-10 emissions from sources within the Vaal Triangle using a Geographic Information System (GIS). The emission inventory compiled by van Nierop for the calendar year of 1992 (van Nierop, 1994) was used as input data for these calculations. The Industrial Source Complex Short Term Model (ISCST) was applied for dispersion calculations of annual PM-10 emissions. The ReGIS package was applied to determine the applicability of GIS as a management tool. Annual average PM-10 concentration contours were calculated for the different air pollution source groups within the Vaal Triangle. The combined source group resulted in the highest population exposure from annual average PM-10 concentrations. Population exposure from high- (> 200 m), medium- (10 to 200 m) and low- (< 10 m) elevation air pollution source groups were determined. The medium-elevation source group resulted in high population exposure followed by the low-elevation source group. The high-elevation source group had very low population exposure as a result. The population exposures from all the industrial sources within the Vaal Triangle were calculated and found to be very high. Annual average PM-10 concentrations from domestic fuel combustion sources were surprisingly low, resulting in low population exposure. ReGIS was found to be inadequate for the task and is not recommended for further use. Despite this, GIS was found to be a powerful decision-making tool and other GIS software packages should be explored for future research