Polycyclic aromatic hydrocarbons in air and snow from Fairbanks, Alaska

Abstract

There has been increasing interest regarding the use of passive air samplers as tools for monitoring organic pollutants in the atmosphere. In this study we report results obtained from passive air samplers that were deployed in both indoor and outdoor environments across the City of Fairbanks, AK, for the polycyclic aromatic hydrocarbons (PAHs) during winter 2009. It is demonstrated that the passive air samplers provide reliable data for the gas-phase PAHs. Results for particulate-phase isomers, however, are more variable and thus likely to be less reliable. For instance, the use of passive air samplers in indoor environments does not appear effective for distinguishing between homes with and without wood stoves, largely due to discrepancies associated with measuring particulatephase PAHs. Consequently, it is suggested that the passive air samplers should not be used for assessing indoor exposures to particulate-bound pollutants. Nevertheless, air concentrations obtained from active air samplers indicate that PAHs in air are dominated by the gas-phase isomers, resulting in good agreement between the active and passive air samplers for outdoor air. The average passive indoor air concentrations for ΣPAH20 are observed to be slightly higher than passive outdoor air concentrations, at 55 and 26ng m-3 respectively. Concentrations in outdoor air for the City of Fairbanks are reported to be an order of magnitude lower during 2009 than during the winter of 1976/77, when they were last reported. Snow data for the PAHs are reported as a complement to the air concentration data, showing similar isomer patterns between air and undisturbed snowpack samples. Snow samples collected from snow dump collection sites are reported to be 25 times greater than nearby undisturbed snow, and are dominated by the particulate-phase PAHs. Recommendations for future monitoring of snowmelt from the snow dump collection sites are suggested.