The impact of BTEX emissions from gas stations into the atmosphere

Abstract

Gas stations in Brazil are commonly located in residential and commercial areas, which lead to the degradation of health quality for people who live and work in the neighborhood. In this study, eleven gas stations located at Rio de Janeiro, Brazil, were evaluated. Forty–nine samples were collected in the gas station area and others 250m away from one of the studied areas to evaluate the plume dispersion of the contaminants emitted during the filling process. This study focused on the BTEX (benzene, toluene, ethyl benzene and xylenes) emissions, as content of these compounds in gasoline sold in Brazil is near 40% v/v. Samples were collected using coconut shell charcoal cartridges, and the chemical analyses were done using a GC–MS technique after sample extraction with dichloromethane. Results indicated an average value of 29.7μg m−3 for benzene, 47.7μg m−3 for toluene, 23.3μg m−3 for ethyl benzene, 46.9μg m−3 for m+p–xylene and 14.3μg m−3 for o–xylene. The concentrations of the saturated vapors of five commercial gasoline samples were evaluated by using the static headspace technique. Ambient air concentrations estimated using a Gaussian plume dispersion model indicated that values for BTEX were greater than those found in the downtown area of Rio de Janeiro, even 150m away from the gas station which can impact a nearby hospital, two schools and several residences. These results indicated that more attention should be given to the locations of gas stations.