AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Chemical and Microphysical Properties of Wind-blown Dust Near an Actively Retreating Glacier in Yukon, Canada
PATRICK HAYES, Jill Bachelder, Malo Bernhard, Carolyn Liu-Kang, Pérrine Lambert, Alexane Filoche, Juliana Galhardi, Madjid Hadioui, Marie Cadieux, Amélie Chaput, Marie-Pierre Bastien-Thibault, Kevin Wilkinson, James King, Université de Montréal
Abstract Number: 862 Working Group: Remote and Regional Atmospheric Aerosol
Abstract Airborne mineral aerosols emitted in high-latitude regions can impact radiative forcing, biogeochemical cycling of metals, and local air quality. The impact of dust emissions in these regions on the atmosphere and environment may change rapidly, as warming temperatures can increase mineral dust production and source regions. As there exists little research on mineral dust emissions in high-latitude regions, we have performed the first study of the physico-chemical properties of mineral dust emitted from a sub-Arctic proglacial dust source. Soil and aerosol samples (both PM10 and deposited mineral dust) were collected in May 2018 and 2019 near the Ä’äy Chù (Slims River), a site that has exhibited strong dust emissions. WHO air quality thresholds were exceeded at several receptor sites near the dust source, indicating a negative impact on local air quality. Notably, temporally averaged particle size distributions of PM10 were very fine as compared to those generally measured at low-latitude dust sources. Mineralogy of ambient PM10 comprised primarily clay mineral aggregates, while PM10 elemental composition was enriched in trace elements as compared to deposited dust, bulk soil samples, and the fine soil fraction (d < 53 µm). Finally, using analyses of the elemental composition of the soils and of the PM10, of the ambient PM10 particle size distribution, and of meteorological factors measured during our sampling campaign, we propose that the primary mechanisms for dust emissions from the Ä’äy Chù Valley are the rupture of clay coatings on particles and/or the release of resident fine particulate matter.