Surface and Bulk chemistry relevant to atmospheric aerosol systems that impact the air quality, climate and health

由于其高度复杂的物理化学性质，大气气溶胶系统对空气质量、气候以及人类和生态健康的总体影响仍然不确定。国家和国际层面的监管机构使用的新政策和模型需要以考虑气溶胶老化的实验数据为基础。“老化”一词指的是改变大气中气溶胶特性的过程，这个过程可能长达两周。这些过程可以发生在颗粒/液滴的表面或在凝聚相内。这些反应的程度和速率受水的含量和化学成分的影响。在这些体系中，金属和有机物的反应性产生的活性氧可以改变光学性质、化学成分，从而改变冰/云的成核效率。此外，气溶胶颗粒可传播空气传播疾病，吸入后对呼吸器官造成损害。根据最近现场测量的结果和改善大气化学模型中气溶胶表征的需要，我的NSERC DG的更新申请将支持实验室实验和现场测量，这些实验和测量具有假设和发现为基础的方面，解决了目前在气溶胶物理特性、化学反应性和生物含量相互作用方面的知识空白。我们的长期目标是通过精心设计的实验和战略规划的实地活动，改善气候和污染物运输模型中多组分气溶胶系统的参数化，并影响城市和区域层面的气候行动计划。短期目标分为三个主要主题：（基于假设的主题1）模型两相气溶胶系统中铁溶解和金属催化新颗粒形成的效率；（基于发现的主题2）基奇纳气溶胶颗粒的尺寸依赖性收集和分析；（基于发现的主题3）细颗粒物（PM）提取物微滴的化学性质。结果将在大气气溶胶化学领域具有重要意义和影响力，因为它们将提供目前模型中缺失的含过渡金属的多组分气溶胶反应性和物理性质的机理细节。研究结果还将告知当地城市、地区政府和学校董事会，学校附近和学校内部的细颗粒物的化学和生物活性，从而影响户外活动项目的新举措、学校通风系统的效率、课程和学生生活实验室的发展，旨在提高对空气质量和细颗粒物对健康影响的认识。

The overall impact of atmospheric aerosol systems on air quality, climate and human and ecological health remains uncertain due to their highly complex physicochemical properties. New policies and models used by regulators at the national and international levels need to be based on experimental data that account for aerosol aging. The term `aging' refers to the processes that change aerosol properties in the atmosphere, which can be as long as two weeks. These processes can take place at the surface of the particles/droplets or within the condensed phase. The extent and rates of these reactions are influenced by water content and chemical composition. The reactivity of metals and organics in these systems produce reactive oxygen species that can change the optical properties, chemical composition, and hence, ice/cloud nucleation efficiency. Also, aerosol particles can transmit airborne diseases and cause damage to the respiratory organs upon inhalation. Guided by recent results from field measurements and needs for improving aerosol representation in atmospheric chemistry models, this renewal application for my NSERC DG will support lab experiments and field measurements that have hypothesis- and discovery-based aspects that address current gaps in knowledge pertaining to the interplay of aerosol physical properties, chemical reactivity, and biological content. Our long term objective is to improve the parameterization of multicomponent aerosol systems in climate and pollutant transport models and influence climate action plans at the city and regional levels through carefully-designed experiments and strategically-planned field campaigns. The short term objectives fall into three main themes: (HYPOTHESIS-BASED THEME 1) Efficiency of iron dissolution and metal-catalyzed new particle formation in model two-phase aerosol systems, (DISCOVERY-BASED THEME 2) Size-dependent collection and analysis of aerosol particles in Kitchener, ON, and (DISCOVERY-BASED THEME 3) Chemistry of microdroplets from fine particulate matter (PM) extracts. Results will be significant and impactful in the field of atmospheric aerosol chemistry as they will provide mechanistic details on transition metal-containing multicomponent aerosol reactivity and physical properties currently missing in models. The results will also inform local city, regional governments, and school boards of chemical and biological activity of fine PM near and inside schools to influence new initiatives on outdoor activity programs, efficiency of ventilation systems in schools, curriculum and living lab devolvement for school kids aimed at increasing awareness of air quality and health impacts of fine PM.