Temporal and geographic variation in aeroallergen measurements across four Canadian cities from 2008-2012

Fungal spores and pollen from trees, grasses, and weeds are associated with outdoor environmental allergies in Canada. These aeroallergens typically have a distinct temporal pattern across geographical regions. This study describes seasonal and geographic variation in aeroallergens from 2008-2012 in the Canadian cities of Vancouver, Edmonton, Winnipeg, and Toronto. The study period and study locations were chosen to characterize the potential aeroallergen exposures of participants in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort. Seasonal exposures in Vancouver were the longest for every group of aeroallergens, except grasses. Vancouver was also the highest for the trees pollen. Total fungal spore concentrations were higher in Edmonton, Winnipeg, and Toronto than in Vancouver. The differences recorded in this study across geographical regions may be significant for the CHILD participants if they lead to distinct and clinically important windows of exposure for infant immune response and subsequent differential risk of allergenic disease.