Assessing Above-Ground Fuel Storage Tank Emissions Using Lower-Cost Sensor Packages and Triggered Canister Samples

Fuel
tank terminals provide storage during the 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 are 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
(PID) sensors during high concentration events. This study is the
first to characterize long-term fuel terminal (FTs) emissions using
lower-cost remote sensing. Gasoline headspace compounds represented
95–97% of the 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 the 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.