Determinants of airborne concentrations of volatile organic compounds in rural areas of Western Canada.

摘要

We estimated the level and determinants of airborne concentrations of 26 volatile organic compounds (VOC) in rural Western Canada. A multisite, multimonth unbalanced two-factorial design was used to collect air samples at 1206 fixed sites across a geographic area associated with primary oil and gas industry in Alberta, northeastern British Columbia, and central and southern Saskatchewan from April 2001 to December 2002. Principal component factor analysis was used to group VOC into three mixtures. Factor I was a group of compounds dominated by benzene, toluene, ethyl-benzene, xylenes, and hexane. Factor II was mainly a group of vegetation-related monoterpenes and dichlorobenzenes. Factor III was a group of chlorinated VOC. Linear mixed effects models were applied to identify the determinants of airborne concentrations of VOC and evaluate the association between these factors and oil and gas facilities. Our results indicated that the studied VOC were present in small (ng/m(3)) quantities. Components of Factor I VOC showed a seasonal variation with maxima in winter and minima in summer, whereas components of Factor II displayed an opposite seasonal trend. Components of Factor III did not show a clear seasonal pattern. We observed that oil and gas facilities only contribute to airborne concentrations of components of Factor I. Proximity to batteries (within 2 km) was most influential in determining monthly airborne concentrations of components of Factor I, followed by gas and oil wells. Modification of batteries to reduce evaporation and leakage might be considered as a measure to control airborne concentrations of compounds such as benzene and toluene.Journal of Exposure Science and Environmental Epidemiology (2008) 18, 117-128; doi:10.1038/sj.jes.7500556; published online 28 February 2007.