Source apportionment of hydrogen sulphide at Elandsfontein in Mpumalanga Highveld
As far as the candidate could assess, no H?S source apportionment has been conducted for the Mpumalanga Highveld, an area with known air quality problems. The lack of such assessments is due to current receptor-oriented methods not being ideal for source apportionment of trace gases and the absence of a comprehensive South African specific emission inventory in the peer reviewed public domain, which is vital for source-oriented models. In this study, a relatively recently published receptor-oriented source apportionment method, which is applied to conduct equivalent black carbon (eBC) source apportionment, was further developed to enable source apportionment of trace gases. This improved method was successfully applied to conduct H?S receptor-oriented source apportionment on a data set that was gathered during the European Integrated Project on Cloud Climate, Aerosols and Air Quality (EUCAARI) project at the Elandsfontein measurement station on the Mpumalanga Highveld. The results proved that urban emissions (associated with towns, as well as semi- and informal settlements, waste water treatment facilities, landfills, small industries and traffic) contributed most to ambient H?S (41.3% in excess of the baseline), followed by the Johannesburg-Pretoria conurbation (15.3%) and the petrochemical operation near Secunda (14.3%). Pyrometallurgical smelters, coal-fired power stations and cattle feedlots contributed 11.2, 5.9 and 1.0% to ambient H?S in excess of the baseline, respectively. A total of 89% of the measured ambient H?S in excess of the baseline was attributed to specific sources, proving that the developed method is an effective tool for source apportionment of trace gases.