Exposure to volatile organic compounds (VOCs) at gas stations: a probabilistic analysis

Abstract

Gasoline evaporation and spills may cause high air pollution at gas stations. This study aimed to assess exposure to volatile organic compounds (VOCs) at gas stations among customers. Ambient air samples were collected in the fuel dispensing area of 51 gas stations in the Greater Memphis Area, USA, in summer 2017. For the comparison purpose, samples were collected in the ambient air at 20 community sites and in the indoor air of 30 homes, 11 offices, and 15 running vehicles in the same region. Air sampling used Tenax TA thermal desorption (TD) tubes and samples were analyzed by TD-gas chromatography/mass spectrometry (GC/MS) for 70 target compounds. Gasoline-related VOCs were identified using factor analysis, and exposure at gas stations was evaluated using Monte Carlo analysis. Benzene, toluene, ethylbenzene, and xylenes (BTEX) showed the highest concentrations ranging from 2 to 15 μg/m3, ten times higher than those in the community air. Factor analysis confirmed gasoline as the common source of aromatic compounds. VOC concentrations had no association with the number of cars present or environmental parameters. Exposure to aromatic compounds at gas stations represented 2% of the total exposure (i.e., the sum of indoor and outdoor exposures) but 38% of the outdoor exposure among customers. The exposure levels were below the acute health thresholds and presented 0.3 × 10−6 lifetime excess cancer risk. In conclusion, customers’ exposure to VOCs at gas stations has negligible non-cancer and cancer risks. It is also suggested that customers stand away from the nozzle to avoid high personal exposures during refueling.

Publication Title

Air Quality, Atmosphere and Health

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