Atmospheric measurements and modeling studies to improve understanding of organic and mineral dust aerosols in northern Canada

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Atmospheric aerosols, tiny airborne particles, have an important impact on air quality (AQ) and the Earth's climate. Exposure to aerosols causes increased rates of cardiac and respiratory disease and leads to millions of premature deaths globally each year. Aerosols also play an important role in climate change. For example, absorption of light by mineral dust warms the planet's atmosphere, and when deposited on snow or ice, mineral dust accelerates the melting of these reflective surfaces leading to warming of the Earth's surface. Models used by scientists to predict climate and AQ typically include modules for numerically simulating aerosols. However, the performance of these modules is often poor when used to predict aerosol composition and concentration due to the complexity of aerosol chemistry and missing aerosol sources. To address this challenge, the Hayes Group will pursue two research goals. First, mineral dust emitted from arctic and subarctic regions is a missing aerosol source in most climate and AQ models because of a lack of field measurements needed for model improvement. As Canada's north warms, it will likely become an increasingly important source of mineral dust aerosol due to reduced snow and ice cover, which exposes bare soils easily eroded by winds. My group will develop techniques and perform fieldwork to measure the concentrations and light-absorbing properties of mineral dust aerosol emitted in Canada's north in the Yukon and Nunavut. Our data will be used to constrain and inform the development of climate and AQ models, resulting in important research contributions towards better simulating emissions of mineral dust in arctic and subarctic regions. Another aerosol source that is uncertain in climate and AQ models is the photo-chemical oxidation of organic vapors to produce secondary organic aerosol (SOA). For example, field measurements in the Oil Sands show high concentrations of SOA similar to those found in Toronto, while Canadian AQ models predict much lower levels. The Hayes Group will organize, analyze and model extensive datasets already collected on SOA across Canada and near the Oil Sands to update the numerical aerosol simulation module in a Canadian AQ model. This work will not only improve AQ predictions but also provide a deeper understanding of the chemistry and sources producing SOA near the Oil Sands. The activities described above will be realized by students at Université de Montréal working in close collaboration with government scientists and researchers at other universities across Canada. The students will receive strong interdisciplinary training in analytical and atmospheric chemistry. There are also opportunities for group members to learn about computer programming, data science, and northern cultures and communities. These skills and experiences will all be valuable to have in the future Canadian workforce in both the public and private sectors.