CAREER: Air-Quality Effects of Atmospheric Chlorine Chemistry

该职业奖包括实验室实验、环境测量和模型研究，以调查氯化学在环境空气中颗粒物和臭氧形成中的作用。质谱学技术的最新发展将被用来研究由于环境氯化学而形成的高度氧化的分子。该项目的结果可以用于空气质量模型，以便在更知情的情况下做出关于环境政策的决策。在实验室中，将使用最先进的高分辨率化学电离质谱仪(HR-CIMS)对不同前体形成的气相和颗粒相中的高度氧化分子(HOM)进行详细的分析和测量。首席研究人员假设，氯显著增加了HOM、臭氧和有机颗粒物的浓度。她还计划研究不同前体在不同实验条件下由于氯的存在而形成的烷基硝酸盐的浓度和组成的变化。将进行环境测量，以观察石油和天然气生产区域中的氯化学并量化含氯物种。首席研究员建议对实验室室内实验进行模拟，以量化初始碳氢化合物与氯或羟基反应的比例，以及随后的化学反应(例如，产物物种的持续氧化)由于与氯或羟基反应而进行的程度。这将使评估氯直接氧化的相对重要性与其通过二次生成OH所产生的影响的相对重要性。她还计划开发可用于化学传输模型的参数，以解释由氯引发的碳氢化合物氧化形成的二次有机气溶胶。

This CAREER award includes laboratory experiments, ambient measurements, and modeling studies to investigate the role of chlorine chemistry in the formation of particulate matter and ozone in ambient air. The latest developments in mass spectrometric techniques will be used to investigate the formation of highly oxidized molecules as a result of ambient chlorine chemistry. Results from this project can be used in air quality models to make better-informed decisions about environmental policies. Detailed analyses and measurements of highly oxidized molecules (HOM) in the gas and particle phases formed from different precursors, with and without the addition of Cl, will be performed in the laboratory chamber using a state-of-the-art high-resolution chemical ionization mass spectrometer (HR-CIMS). The principal investigator hypothesizes that Cl significantly enhances concentrations of HOM, ozone and organic particulate matter. She also plans to investigate changes in the concentration and composition of alkyl nitrates formed from different precursors and under different experimental conditions due to the presence of Cl. Ambient measurements will be conducted to observe Cl chemistry and quantify chlorine-containing species in an oil and gas production region. The principal investigator recommends to model laboratory chamber experiments to quantify the fraction of the initial hydrocarbon reacting with Cl versus OH, as well as the extent to which the succeeding chemistry (e.g. continued oxidation of product species) proceeds due to reaction with Cl or OH. This will enable the evaluation of the relative importance of direct oxidation by Cl versus its effect through secondary OH production. She also plans to develop parameterizations that can be used in chemical transport models to account for formation of secondary organic aerosol from Cl-initiated oxidation of hydrocarbons.