Understanding Ambient and Settled Dust in Communities Near Intensive Resource Development to Improve Monitoring and Mitigation

Airborne and settled dust pose a significant environmental problem in areas with disturbed crustal material due to human-related or natural activities. Climate and landscape changes may increase dust issues globally. Fort McKay, an Indigenous and Métis community in the Canadian Athabasca Oil Sands Region has experienced elevated dust levels for decades, with growing concerns. This study combines two years of ambient particulate matter (PM) measurements resolving different particle sizes and time scales with monthly dustfall samples to document community-level burden and to better characterize dust deposition events to improve monitoring and mitigation strategies. Monthly dustfall was high throughout Fort McKay, frequently exceeded residential guidelines, and was higher than other monitoring locations in the region. Deposition estimates based on ambient PM data show deposition is dominated by PM >10 though consistent underestimation highlights methodological limitations. Analysis of 24-hr integrated PM samples reveals strong episodicity in dust deposition events: ∼40% of days account for 75% of cumulative PM mass, where hourly data show that 30% of hours accounted for the same proportion of PM 2.5-10 mass. Dust events last on average 3.5 ± 1.2 hours and are characterized by short-lived but intense peaks. Moderate correlations (r=0.62) and similar episodicity between PM 2.5-10 and PM >10 suggest that PM 2.5-10 can be a reasonable surrogate for PM >10 , helping identify dust events and track deposition changes in real time. These findings highlight the need to capture episodic, coarse-mode PM exposures in dust-impacted regions and implement targeted monitoring and regulatory frameworks to address disproportionate exposure burdens in nearby communities.