Laboratory Studies of Heterogeneous Oxidation of Organic Aerosols

本项目主要研究有机气溶胶中特定化合物的寿命和化学降解途径。提出的研究有两个主要目标。第一个是利用复杂的、与大气相关的混合物进行控制良好的实验，以帮助弥合简单系统的现有实验室数据与大气观测之间的差距。为了更好地模拟实际的大气老化，将测量两种复杂混合物（机油和肉类烹饪油脂）产生的气溶胶颗粒中大约30种有机化合物的衰减率。这些混合物含有数千种单独的有机物，是重要类别的初级有机气溶胶的替代品。新数据将与简单系统的现有数据进行比较，以评估非均质老化对大气气溶胶成分的重要性。第二个主要目的是研究羟基（OH）自由基的非均相氧化。OH可能是最重要的氧化剂，因为绝大多数已确定的有机气溶胶是由饱和化合物组成的。这将通过对雾化机油和简单工程混合物进行烟雾室实验来进行调查。空气中的微粒影响气候、降低能见度并影响人类健康。这些结果将有助于改进用于了解有机气溶胶起源的大气模型。这些模型被广泛用于评估气溶胶对全球气候、区域能见度和空气质量的潜在影响，这些都是重要的社会问题。该项目还将支持一些本科生和研究生的教育。

This project is focused on investigating the lifetimes and chemical degradation pathways of specific compounds in organic aerosols. There are two major objectives of the proposed research. The first is to conduct well-controlled experiments using complex, atmospherically relevant mixtures to help bridge the gap between existing laboratory data on simple systems and atmospheric observations. To better simulate actual atmospheric aging, the decay rate will be measured for approximately 30 organic compounds in aerosol particles generated from two complex mixtures: motor oil and meat cooking grease. These mixtures contain thousands of individual organics and are surrogates for important classes of primary organic aerosol. The new data will be compared to existing data for simple systems to assess the significance of heterogeneous aging on atmospheric aerosol composition. The second major objective is to investigate heterogeneous oxidation by hydroxyl (OH) radicals. OH may be the most important oxidant given that the vast majority of the identified organic aerosol mass is comprised of saturated compounds. This will be investigated by conducting smog chamber experiments with aerosolized motor oil and simple engineered mixtures.Airborne particles influence climate, degrade visibility, and impact human health. The results will help improve atmospheric models used to understand the origin of organic aerosols. These models are widely used to assess the potential effects of aerosols on global climate, regional visibility, and air quality, which are all important societal problems. The project will also support the education of a number of undergraduate and graduate students.