Field and laboratory studies of aerosol formation from halogenated precursor gases

该项目在野外和实验室研究中调查了卤化前体气体形成的二次气溶胶及其对对流层卤素化学的影响。将其纳入旨在了解自然卤化过程中普遍存在的反应机制的HaloProc研究单位，主要目的是增进对碘引发的新粒子形成的理解。在具有有机碘化合物生物来源的沿海环境中，以前曾观察到活性碘物种的气溶胶粒子成核。在这里，我们建议研究盐湖环境中新的颗粒形成事件，这些事件可能由活性碘化合物的无机来源主导。将测量亚微米颗粒尺寸分布的时间演变，并收集气溶胶过滤器样本用于后续的化学分析。为模拟实地遇到的大气条件而设计的补充实验室实验，并配备更复杂的分析方法，将有助于确定相关的碘物种和碘引发的新颗粒形成的关键反应机制。通过实地工作和实验室工作的结合，预计将向模型界提供一组广泛的实验数据，以便更深入地了解碘成核对对流层卤素化学的影响。因此，拟议的研究议程旨在弥合实地实验、实验室研究和建模工作之间的差距，并有助于实现HaloProc研究股的总体目标。

This project investigates secondary aerosol formation from halogenated precursor gases and its impact on halogen chemistry in the troposphere both in field and laboratory studies. Embedded into the HaloProc research unit which aims at understanding the reaction mechanisms prevailing in natural halogenation processes, the main objective is an improved understanding of iodine-initiated new particle formation. Nucleation of aerosol particles from reactive iodine species has previously been observed in coastal environments with biogenic sources of organic iodine compounds. Here, we propose to study new particle formation events in salt lake environments that may be dominated by inorganic sources of reactive iodine compounds. The temporal evolution of submicron particle size distributions will be measured, and aerosol filter samples will be collected for subsequent chemical analysis. Supplementary laboratory experiments designed to simulate the atmospheric conditions encountered at the field sites, and equipped with more sophisticated analytical methods, will help to identify the relevant iodine species and the key reaction mechanisms for iodine-initiated new particle formation. From the combination of field and laboratory work, an extensive set of experimental data is expected that will be made available to the modeling community in order to gain deeper insight into the implications of iodine nucleation on halogen chemistry in the troposphere. Thus, the proposed research agenda is designed to bridge the gap between field experiments, laboratory studies and modeling work, and contribute to the overarching objectives of the HaloProc research unit.