BTEX concentrations influenced by external factors at a diesel-refuelling station in Johannesburg, South Africa

Public transport systems in Johannesburg, South Africa, rely on a large number of diesel-powered buses. These buses are fuel economical and durable. However, filling station attendants, bus drivers and the public are exposed to the diesel fuel and fumes associated with them. Fuel attendants are exposed to diesel exhaust fumes, as well as emissions from fuel pumps on a daily basis, and are at risk to adverse health effects associated with inhalation of volatile organic compounds (VOCs) released. The VOCs released include benzene, toluene, ethyl-benzene and xylenes (BTEX), which have a high level of toxicity. Studies relating to the concentrations of BTEX at diesel stations are limited, as most studies focus on petrol refuelling stations. Thus, analyses of these concentrations are significant within developing countries whose transport systems rely on diesel-powered buses, and where public health measures are often less rigorously enforced. As this research falls within a larger study relating to the health impact of BTEX on fuel attendants at a diesel-refuelling bay, an initial study was undertaken to analyse the two main external factors that are influential on fluctuations of ambient concentrations. Thus, an analysis of total volume dispensed, and ambient temperature at the station, both affecting the concentrations of BTEX released, was conducted. It was established that BTEX_total concentrations were positively correlated to the volume of diesel dispensed daily and inversely correlated to temperature. Additionally, ethylbenzene and o-xylene indicated a positive correlation with volume of fuel dispensed, while toluene and p-xylene were negatively correlated to temperature.