Source apportionment of volatile organic compounds measured in downtown calgary.
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Twenty four-hr VOC mass concentrations measured at Calgary downtown monitoring site between 2004 and 2011 were analyzed using a receptor model. Calgary downtown was comprised largely of a dense business district. Vehicular traffic in and out of downtown is likely higher during the weekdays. In the downtown core and surrounding areas there are a number of commercial activities. Outside of the city there are a number of oil and gas activities that may contribute to the observed VOC or their precursors' concentration at the downtown site. The final source apportionment solution contained 10 factors with key species that help group the identified factors into the following categories, i.e., transportation, fugitive, biogenic, global or carry over. The transportation factors on average contributed the most to the reconstructed mass, however a significant decrease over time was observed for this factor. Key species in the carryover factors implied these factors are likely associated with processed air mass. This group of factors contributed on average the second highest reconstructed mass. The fugitive factors were likely associated with commercial activities; both were identified by notable contribution from key VOC specie, i.e., toluene and tetracholorethylene. The biogenic factor contributed the least to the reconstructed mass contribution, but was readily identified by its key specie isoprene and clear seasonal variability. This is an abstract of a paper presented at the AWMA's 107th Annual Conference & Exhibition (Long Beach, CA 6/24-27/2014).