Assessing above-ground fuel storage tank emissions using lower-cost sensor packages and triggered canister samples

Fuel tank terminals provide storage during refined petroleum transport. These sources emit volatile organic compounds (VOCs) that contribute to regional ground-level ozone formation and include some hazardous air pollutants (HAPs, estimated to be 3-4% w/w). Emissions are accounted for using inventories but not routinely measured owing to safety concerns. We conducted a 1.5-year study in Greensboro, NC that measured and chemically speciated VOCs near fuel tanks using canister samples triggered by photoionization detector sensors during high concentration events. This study is the first to characterize long-term fuel terminal emissions using lower-cost remote sensing. Gasoline headspace compounds represented 95-97% of canister composition by site median volume concentration. Butane, iso-pentane, n-pentane, isobutane, ethanol, and 2-methylpentane (in order) showed highest median concentrations at all sites equipped with canister capability. Trans-2-pentene, trans-2-butene, and m- and p-xylenes were the largest contributors to estimated ground-level ozone. These hybrid measurement-modeling approaches may be employed in other airsheds to garner VOC information over long periods and to identify compounds of concern.