Evaporative Losses from Retail Gasoline Outlets and Their Potential Impact on Ambient and Indoor Air Quality

Abstract

Retail gasoline outlets contribute to the emission of volatile organic compounds (VOCs). According to the United States Environmental Protection Agency (US EPA), the concentrations of the common constituents of gasoline such as benzene (a carcinogen), toluene, ethylbenzene, and xylene within 200 m of gas stations are found to be higher than ambient background levels. Many retail gasoline outlets are located in close proximity to populated commercial and residential neighbourhoods. In the light of the above, this paper presents estimates from the survey of industrial processes (SIP), a pilot survey conducted by the Canadian Government, for the overall evaporative emissions from retail gasoline outlets across Canada. The survey suggests that approximately 58 million litres of liquid gasoline is being evaporated each year into the ambient air from the 11,200 retail gasoline outlets across Canada. Such an emission rate is equivalent to the evaporation of the contents of three fully loaded gasoline delivery trucks on each and every day of the year. This silent emission contaminates the ambient air of urban populated neighbourhoods and subsequently the indoor air of buildings that are located in such neighbourhoods. To that end, this paper attempts to raise the awareness of building engineers regarding the locations of gasoline outlets within the vicinity of buildings and the potential short-circuiting of gasoline vapours from the ambient air to the indoor microenvironment.