Multiphase Chemistry and Atmospheric Particles: Reactive Species, Oxidation and Impacts

虽然大气颗粒物对人类健康和全球气候都至关重要，但它们在大气中的详细化学性质还没有得到很好的表征。特别是，一旦颗粒形成，它们就会受到大气氧化过程的影响，这可能会改变它们的组成和化学性质。为了将气候和空气质量模型置于坚实的基础之上，需要了解这些过程的化学过程。因此，建议进行一系列新颖的实验室实验，以更全面地了解大气气溶胶氧化的机制及其对大气的潜在影响。 具体项目将评估：i）气溶胶的有色组分的速率和机制，（即“棕碳”）在气溶胶颗粒和云中将被化学改变，ii）氧化在影响颗粒作为冰云成核位点的能力中所起的作用，iii）颗粒中反应性含氧物质的形成速率，和iv）从气相到气溶胶颗粒的反应性自由基的吸收速率。 这种化学作用将对周围大气气溶胶的成分、吸湿性、光学特性和毒性产生影响。 国家的最先进的仪器将用于本研究计划，特别是使用新的在线和离线质谱方法。沿着合作机会，这将为学员提供先进分析方法的背景知识。 这项研究计划的总体影响将进一步发展我们对人类活动如何影响自然环境的基本理解。

Although atmospheric particles are of crucial importance to both human health and global climate, their detailed chemistry in the atmosphere is not well characterized. In particular, once particles are formed, they are subject to atmospheric oxidative processes that may alter their composition and chemical properties. To place climate and air quality models on a firm fundamental foundation, the chemistry of these processes needs to be understood. And so, it is proposed to conduct a suite of novel laboratory experiments to provide a more complete view of the mechanisms of atmospheric aerosol oxidation and the potential impacts on the atmosphere. Specific projects will assess: i) the rates and mechanisms by which the coloured components of aerosol (i.e. “brown carbon”) will be chemically altered in aerosol particles and clouds, ii) the role that oxidation plays in affecting the ability of particulates to act as the sites for ice cloud nucleation, iii) the formation rates of reactive oxygenated species in the particle, and iv) the rate of uptake of reactive radicals from the gas phase to the aerosol particle. This chemistry will have impacts on the composition, hygroscopicity, optical properties, and toxicity of ambient atmospheric aerosol. State of the art instrumentation will be used in this research program, in particular the use of both novel on-line and off-line mass spectrometric approaches. Along with collaborative opportunities, this will provide trainees with a background in advanced analytical methods. The overall impact of this research program will be to further develop our fundamental understanding of how anthropogenic activities are impacting our natural environment.