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

大气气溶胶是空气中的微小颗粒，对空气质量(AQ)和地球气候有重要影响。暴露在气雾剂中会增加心脏病和呼吸系统疾病的发病率，并导致全球每年数百万人过早死亡。气溶胶在气候变化中也起着重要作用。例如，矿物尘埃吸收光线使地球大气变暖，当矿物尘埃沉积在雪或冰上时，矿物尘埃加速了这些反射表面的融化，导致地球表面变暖。科学家用来预测气候和空气质量的模型通常包括数值模拟气溶胶的模块。然而，由于气溶胶化学的复杂性和气溶胶来源的缺失，这些模块在用于预测气溶胶成分和浓度时的性能往往很差。 为了应对这一挑战，海斯小组将追求两个研究目标。首先，北极和亚北极地区排放的矿物尘埃是大多数气候和AQ模式中缺失的气溶胶来源，因为缺乏改进模式所需的现场测量。随着加拿大北部变暖，它可能会成为矿物粉尘气溶胶的一个越来越重要的来源，因为冰雪覆盖减少，暴露出裸露的土壤，很容易被风侵蚀。我的团队将开发技术并进行实地工作，以测量加拿大北部育空和努纳武特地区排放的矿物粉尘气溶胶的浓度和吸光性能。我们的数据将被用来约束和告知气候和AQ模型的发展，从而为更好地模拟北极和亚北极地区矿物粉尘的排放做出重要的研究贡献。 另一个在气候和AQ模型中不确定的气溶胶来源是有机蒸气的光化学氧化产生二次有机气溶胶(SOA)。例如，油砂的现场测量显示，与多伦多发现的浓度类似，SOA浓度很高，而加拿大的AQ模型预测的浓度要低得多。海斯小组将组织、分析和模拟已经在加拿大各地和油砂附近收集的大量关于SOA的数据集，以更新加拿大AQ模式中的气溶胶数值模拟模块。这项工作不仅将改进AQ预测，还将提供对油砂附近产生SOA的化学和来源的更深层次的了解。 上述活动将由蒙大略大学的学生与政府科学家和加拿大各地其他大学的研究人员密切合作来实现。学生将在分析和大气化学方面接受强有力的跨学科培训。小组成员还有机会了解计算机编程、数据科学以及北方文化和社区。这些技能和经验对未来加拿大公共和私营部门的劳动力都将是有价值的。

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.