Seasonal variations of volatile organic compounds in Edmonton, Alberta

Seasonal variations of volatile organic compound (VOC) concentrations were analyzed at two sites in Edmonton, Alberta, Canada, from 1991 to 1993. At the downtown site, maximum values occur in winter and minimum values in summer. These seasonal changes at the downtown site appear to be primarily due to meteorology. Seasonal changes cannot be detected at the industrial site owing to the nearby industrial emissions which may be higher in summer. The contribution by hydrocarbon class at the two sites to the total lifetime VOC-related cancer risk and ozone generation potential are very different, although the total risk and the incremental ozone formation potential are similar. Hence, plans for controlling VOC, to reduce anthropogenically produced O3 or to reduce health risks must address the differences in emission species and rates at different locations.