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Volume 11 (2011), Pages 2536-2549
Research Article

Spatial Variability and Application of Ratios between BTEX in Two Canadian Cities

1Department of Civil and Environmental Engineering, University of Windsor, Windsor, ON, N9B 3P4, Canada
2Air Health Science Division, Health Canada, Ottawa, ON, K1A 0K9, Canada
3Department of Geography, Nipissing University, North Bay, ON, N1B 8L7, Canada
4Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON, N9B 3P4, Canada
5Department of Geography, University of Western Ontario, London, Ontario, Canada

Received 5 November 2011; Accepted 23 December 2011

Academic Editor: Ki-Hyun Kim

Copyright © 2011 Lindsay Miller et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Spatial monitoring campaigns of volatile organic compounds were carried out in two similarly sized urban industrial cities, Windsor and Sarnia, ON, Canada. For Windsor, data were obtained for all four seasons at approximately 50 sites in each season (winter, spring, summer, and fall) over a three-year period (2004, 2005, and 2006) for a total of 12 sampling sessions. Sampling in Sarnia took place at 37 monitoring sites in fall 2005. In both cities, passive sampling was done using 3M 3500 organic vapor samplers. This paper characterizes benzene, toluene, ethylbenzene, o, and (m + p)-xylene (BTEX) concentrations and relationships among BTEX species in the two cities during the fall sampling periods. BTEX concentration levels and rank order among the species were similar between the two cities. In Sarnia, the relationships between the BTEX species varied depending on location. Correlation analysis between land use and concentration ratios showed a strong influence from local industries. Use one of the ratios between the BTEX species to diagnose photochemical age may be biased due to point source emissions, for example, 53 tonnes of benzene and 86 tonnes of toluene in Sarnia. However, considering multiple ratios leads to better conclusions regarding photochemical aging. Ratios obtained in the sampling campaigns showed significant deviation from those obtained at central monitoring stations, with less difference in the (m + p)/E ratio but better overall agreement in Windsor than in Sarnia.