10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Persistence of Wildfire-derived Pollutants in Indoor Environments
LUKAS KOHL, Meng Meng, Joan de Vera, Bridget Bergquist, Colin A. Cooke, Sarah Hustins, Brian Jackson, Arthur W. H. Chan, University of Toronto
Abstract Number: 1606 Working Group: Indoor Aerosols
Abstract The 2016 wildfire in Fort McMurray was the costliest disaster in Canadian history, forced the evacuation of all 88 000 residents, and destroyed 15 % of the town’s the built structures. Re-entry was delayed after initial tests revealed elevated concentrations of organic and inorganic pollutants, including the toxic elements chromium (Cr), arsenic (As), and antimony (Sb). Currently, there are no studies that investigate how long wild-fire derived pollutants are retained in indoor environments, and if they represent a long-term health risk to residents.
Here, we report initial results from a house dust sampling campaign carried out 14 months after the fire. We collected house dust samples from the bedrooms of 35 houses using a modified vacuum cleaner. All analyses were conducted in the <150 µm size fraction. Trace elements were quantified by ICP/MS after total digestion with HNO3/H2O2/HF. We compare our house dust results with samples of urban and forest-floor ash collected during the Fort McMurray wildfire, background studies of Canadian houses in locations not affected by wildfires [Rasmussen et al., 2001, 2013], and regulatory guidelines (Alberta Tier 1 guideline for residential soils).
The concentrations of Cr, As, and Sb in house dust collected in Fort McMurray (geom. mean 48, 5.3, and 6.4 ppm) were comparable to those in background studies (geom. mean 101, 7.7, and 5.5 ppm [Rasmussen et al., 2001, 2013]. Ash concentrations of Cr, As, and Sb differed between urban and rural areas. Urban areas exhibited high concentrations (200-3000, 100-1300, and 20-300 ppm; n=3) that exceeded regulatory guidelines (64, 17, and 20 ppm), while concentrations in forest-floor ash samples were typically below those found in house dust samples (7-300, 1-12, and 0.1-3 ppm; n=5).
Overall, our results indicate that very high concentrations of Cr, As, and Sb can be found in ashes from urban, but not rural, areas; however, our data do not provide evidence that these elements persist in house dust over extended periods of time.
[1] Rasmussen, P. E., K. S. Subramanian, and B. J. Jessiman (2001), A multi-element profile of house dust in relation to exterior dust and soils in the city of Ottawa, Canada, Sci. Total Environ., 267(1–3), 125–140, . [2] Rasmussen, P. E., C. Levesque, M. Chénier, H. D. Gardner, H. Jones-Otazo, and S. Petrovic (2013), Canadian House Dust Study: Population-based concentrations, loads and loading rates of arsenic, cadmium, chromium, copper, nickel, lead, and zinc inside urban homes, Sci. Total Environ., 443, 520–529.