Advanced Characterization of Tropospheric Sources

本项目将使用一种新的在线、高分辨率、高特异度、高灵敏度的质子转移飞行时间质谱仪(PTR-TOF-MS)来表征火灾释放的气相和颗粒相半挥发性有机化合物(SVOC)和气相挥发性有机化合物(VOC)。许多活性的SVOC和VOC将比以往任何时候都被识别和量化，以更好地表征烟雾的总体化学和物理性质，更好地了解在生物质燃烧羽流中观察到的主要变化，并改进光化学模型。将开展三项主要活动：(1)在美国林业局维护的大规模生物质燃烧模拟设施中对重要火灾类型进行高质量模拟。(2)在加州大学河滨分校的大气模拟小室中，结合高分辨率气溶胶质谱仪和其他多种测量手段，对生物质烟雾老化前3-4小时内VOC以及气相和颗粒相SVOC的变化进行了量化。(三)在流动实验室内安装其他仪器，用于现场勘探性测量航空器在起飞和降落过程中以及植被、垃圾焚烧和地热源的排放。该项目将导致对地球上最大的微量气体和颗粒物来源之一--生物质燃烧的排放量做出更准确的估计。特别是，将提供臭氧和气溶胶前体的新数据，这是大气建模人员和空气质量官员非常感兴趣的。这些实验将测量第二和第四大类生物质燃烧(分别为烹饪火和作物残渣火)产生的两种重要的生物质燃烧示踪剂(氰化氢和乙腈)的排放量。示踪剂可用于污染源解析，从而改善空气棚管理。化学形态、烟雾演化和来源归属方面都与公共健康、区域能见度和气候有关。该项目将支持一名研究生进行测量，还将在地球观测系统-化学全球化学传输模式的框架内探索最重要的新数据的更广泛影响。合作将涉及加州大学河滨分校、蒙大拿州立大学、美国地质调查局和美国林业局等其他机构。

This project will characterize the gas and particle phase semi-volatile organic compounds (SVOC) and the gas-phase volatile organic compounds (VOC) emitted by fires using a newly available, on-line, high resolution, high specificity, high sensitivity Proton-Transfer Time-Of-Flight Mass Spectrometer (PTR-TOF-MS). Many reactive SVOC and VOC will be identified and quantified than ever before to better characterize the overall chemical and physical properties of smoke, to better understand the major transformations observed in biomass burning plumes, and to improve photochemical models. Three main activities will be undertaken: (1) High quality simulations of important fire types in a large-scale biomass burning simulation facility maintained by the United States Forest Service (USFS). (2) Quantification of the changes in the VOC, and both the gas and particle phase SVOC, during the first 3 to 4 hours of biomass smoke aging in the University of California, Riverside atmospheric simulation chamber in conjunction with high-resolution aerosol mass spectrometry and many other measurements. (3) Installation in a mobile lab with other instruments for exploratory field measurements of the emissions from aircraft during take-off and landing as well as from vegetation, garbage burning, and geothermal sources. The project will lead to more accurate estimates of the emissions from one of Earth's largest sources of trace gases and particles, biomass burning. In particular, new data will be available for ozone and aerosol precursors, which are of great interest to atmospheric modelers and air quality officials. The experiments will measure the emissions of two important biomass burning tracers (hydrogen cyanide and acetonitrile) from the second and fourth largest types of biomass burning (cooking fires and crop residue fires, respectively). The tracers can be used for source apportionment, which can lead to improved air shed management. The chemical speciation, smoke evolution, and source attribution aspects are all relevant to public health, regional visibility, and climate. The project will support a graduate student who will carry out the measurements and will also explore the broader impact of the most significant new data within the framework of the GEOS-Chem global chemistry transport model. Collaborations will involve other institutions such as University of California, Riverside, Montana State University, the U.S. Geological Survey, and the U.S. Forest Service.