Managing ambient air quality at King Shaka International Airport

Abstract

This study was undertaken to gauge the effectiveness of environmental management interventions at the King Shaka International Airport (Durban) by investigating the source of noted exceedances in Particulate Matter (PM10) concentration. The land-use immediately adjacent to the site is predominated with sugarcane cultivation that is burned annually during the winter and spring months. An experiment was conducted to compare the Particulate Matter concentration during the burning and non-burning seasons, and to verify the differences by means of a t-test. Further isolation of the sugarcane burning events were undertaken by using the HYSPLIT trajectory model. The information from these exercises was reviewed alongside the management procedures for sugarcane burning, to confirm adherence. The results of the study indicated that while there is existing functional management of the air quality impacts from sugarcane burning there is still a marked difference in the ambient air quality when the burning occurs. The burning season had an almost twofold increase in the mean daily Particulate Matter concentration as compared to the non-burning season (29.60 μg/m3 vs 18.30 μg/m3). The study considered the impacts of individual burn events to the noted exceedances of the National Ambient Air Quality Standards (NAAQS), but the modelling was inconclusive, suggesting that the impacts noted are from cumulative burning over the season rather than individual burns. The study concludes that the existing management measures provide assurance to legal compliance, but that this may not be enough in terms of duty of care and environmental best practice. There is a need for the scope of the Environmental Management System to be reassessed for the inclusion of other activities within its land parcels, and how these can be monitored in terms of air quality impacts. The study provides insight into the existing management of sugarcane burning and identifies the current impacts as a possible bottleneck to future development within the area. The study also highlighted the need to speed up the current cane removal within the conservation area to minimise ambient air quality impacts.