RAPID: Online Single-particle Measurements of the Chemical Composition, Mixing State, and Ice Nuclei Residues During the FLAME IV Biomass Burning Experiment

这一快速项目包括在米苏拉第四火灾实验室(FLAME IV)对生物质颗粒的化学成分和混合状态进行在线单粒子质谱仪(SP-MS)测量。与卡内基-梅隆大学(CMU)实验室相比，火焰IV提供了一个独特而重要的机会，通过利用广泛的科学家进行的合作同时测量，更全面地了解生物质烟雾的演变。SP-MS将确定当生物质烟雾在一个新的双环境小室系统中被光化学老化时，气溶胶混合状态如何演变。燃烧室将充满各种与全球相关的生物质燃料产生的燃烧烟雾，并稀释到大气浓度。将使用光模拟器灯和可选的添加氧化剂，如羟基自由基和氮氧化物，在室内模拟大气光化学几个小时。双腔室的设计将提供一个不受干扰的气溶胶控制系统，在长达数小时的实验中，可以随时与扰动室中的气溶胶进行比较。通过与来自科罗拉多州立大学的火焰IV参与者的串联实验，SP-MS还将确定新鲜和陈年生物质燃烧烟雾中存在的冰核的化学成分。一套新的气体和气溶胶仪器将被用来在模拟光化学之前、期间和之后彻底表征生物质气溶胶。该仪器包包括一个高分辨率飞行时间气溶胶质谱仪、质子转移反应质谱仪和一个新的单粒子质谱仪。这将是这种新的激光烧蚀气溶胶粒子飞行时间质谱仪(LAAP-TOF)在任何合作实验或现场活动中的首次部署。LAAP-TOF将使人们更好地了解不同燃料的单个颗粒组成和混合状态的变化，这种混合状态在光氧化过程中是如何演变的，以及这种混合状态在有机碳在气相和颗粒相之间的分配中可能起到什么作用。这项研究涉及多个学科，包括化学、燃烧、空气质量工程、大气科学和气候变化。因此，这项研究将对广泛的跨学科领域产生直接影响，包括森林管理、大气化学、云微物理和生物地球化学。该项目将构成至少两篇研究生博士论文的重要部分，以及一名博士后助理的研究。FLAME IV实验的协作性和多学科性质将为我们的参与者提供一个独特的机会，与他们在CMU进行研究期间相比，与更广泛的科学家一起工作。

This RAPID project involves performing online single-particle mass spectrometry (SP-MS) measurements of the chemical composition and mixing state of biomass particles during the fourth Fire Lab At Missoula Experiment (FLAME IV). FLAME IV affords a unique and important opportunity to better understand the evolution of biomass smoke more completely than is possible in the Carnegie-Mellon University (CMU) laboratory, by taking advantage of the collaborative simultaneous measurements conducted by a wide range of scientists. The SP-MS will determine how the aerosol mixing state evolves as the biomass smoke is photochemically aged in a novel twin environmental chamber system. The chambers will be filled with combustion smoke generated from a variety of globally relevant biomass fuels, and diluted to atmospheric concentrations. Atmospheric photochemistry will be simulated in the chambers for several hours using photo-simulator lights and the optional addition of oxidants such as hydroxyl radical and nitrogen oxides. The twin chamber design will provide an unperturbed control aerosol system to which aerosols in the perturbed chamber can be compared at any time during the multi-hour long experiments. Through tandem experiments with FLAME IV participants from Colorado State University, the SP-MS will also determine the chemical composition of ice nuclei present in fresh and aged biomass burning smoke. A novel suite of gas and aerosol instruments will be used to thoroughly characterize the biomass aerosol prior to, during, and after simulated photochemistry. The instrument package includes a High-Resolution Time-Of-Flight Aerosol Mass Spectrometer, Proton-Transfer-Reaction Mass Spectrometer, and a new single-particle mass spectrometer. This will be the first deployment of this new Laser Ablation Aerosol Particle Time-Of-Flight (LAAP-TOF) mass spectrometer in any collaborative experimental or field campaign. The LAAP-TOF will allow better understanding to be gained of the variations in individual particle composition and mixing state for the different fuels tested, how this mixing state evolves during photo-oxidation, and what role this mixing state might play in the partitioning of organic carbon between the gas and particle phases.The research cuts across multiple disciplines including chemistry, combustion, air quality engineering, atmospheric science, and climate change. Thus, this research will have immediate impacts on a wide range of interdisciplinary fields including forest management, atmospheric chemistry, cloud microphysics, and biogeochemistry. The project will compose a significant portion of at least two graduate student Ph.D. dissertations, and the research of one post-doctoral associate. The collaborative and multi-disciplinary nature of the FLAME IV experiment will provide our participants with the unique opportunity to work alongside a wider range of scientists than otherwise possible during their research at CMU.