RAPID: TAG-AMS Measurements of Organic Aerosol during the BEACHON-RoMBAS 2011 Field Campaign

该项目的目的是调查2011年夏季科罗拉多州曼尼托森林排放的挥发性有机前体产生的二次有机气溶胶（soa）的来源、处理和反馈。首席研究员（PI）开发了一种新型的热解吸气溶胶气相色谱仪（TAG）与气溶胶质谱仪（AMS）耦合，用于表征环境气溶胶的有机成分。该项目支持部署TAG-AMS作为BEACHON-RoMBAS（能量、气溶胶、碳、水、有机物和氮的生物-水-大气相互作用-落基山生物成因气溶胶研究）密集野外活动和结果数据解释的一部分。TAG每小时指定环境气溶胶的有机成分，而AMS测量相应的总颗粒物有机物质的质谱。与其他方法相比，使用相同离子源和高分辨率飞行时间质谱仪同时定量有机形态和质量负载，可以提高表征大气中颗粒物有机物质相关来源和化学过程的分辨率。作为CalNex（空气质量和气候变化联系）活动的一部分，TAG-AMS原型仪器于2010年5月和6月在加利福尼亚州帕萨迪纳市成功部署和运行。在BEACHON-RoMBAS期间，TAG-AMS的测量将有助于了解次生生物气溶胶的来源、处理和反馈的总体规划目标。在BEARPEX（生物圈对气溶胶和光化学实验的影响）期间，还将结合先前在加州Blodgett森林进行的TAG和AMS测量结果进行解释。Manitou森林和Blodgett森林均以黄松为主，但在人为大气污染物相对含量和生物源性挥发性有机碳（VOC）排放通量方面存在显著差异。来自这两个站点的组合数据集将产生关于在化学体系中广泛范围内生物前体的SOA生产途径的见解。此外，通过现场部署获得的经验将使PI能够进一步评估新的TAG-AMS系统的性能。该项目的结果将大大提高我们对以下方面的认识和预测能力：生物气体在大气中形成有机颗粒物质的化学过程，这种颗粒物质对云和降水场的影响，以及由此对森林的反馈。该项目将促进PI和其他参与BEACHON-RoMBAS实地活动的参与者之间的新合作。数据解释将在BEARPEX活动期间从测量中获得额外的见解。通过该项目将培养一名博士后，研究成果将被PI纳入课堂教学。PI、合作科学家和学生获得的知识将通过学术出版物广泛传播，从而为大气化学和空气质量社区作出重大贡献。

The objective of this project is to investigate the sources, processing, and feedbacks of secondary organic aerosols (SOAs) that are produced from volatile organic precursors emitted from the Manitou Forest in Colorado during summer 2011. The principal investigator (PI) has developed a novel thermal desorption aerosol gas chromatograph (TAG) coupled to an aerosol mass spectrometer (AMS) that characterizes the organic composition of ambient aerosols. This project supports deployment of TAG-AMS as part of the BEACHON-RoMBAS (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics, and Nitrogen - Rocky Mountain Biogenic Aerosol Study) intensive field campaign and the interpretation of resulting data. The TAG speciates the organic composition of ambient aerosols hourly while the AMS measures mass spectra of the corresponding total particulate organic matter. Relative to other approaches, the simultaneous quantification of organic speciation and mass loading using the same ion source and high-resolution time-of-flight mass spectrometer provides enhanced resolution in characterizing the associated sources and chemical processing of particulate organic matter in the atmosphere. The prototype TAG-AMS instrument was deployed and operated successfully in Pasadena, CA as part of the CalNex (Nexus of Air Quality and Climate Change) campaign during May and June 2010. Measurements with the TAG-AMS during BEACHON-RoMBAS will contribute to the overall programmatic goal of understanding sources, processing, and feedbacks of secondary biogenic aerosols. Results will also be interpreted in conjunction with prior TAG and AMS measurements in the Blodgett Forest in California during BEARPEX (Biosphere Effects on Aerosols and Photochemistry Experiment). Both the Manitou and Blodgett forests are dominated by ponderosa pine but differ significantly in relative amounts of anthropogenic air pollutants and emission fluxes of biogenic volatile organic carbon (VOC). The combined data sets from these two sites will yield insight regarding production pathways for SOA from biogenic precursors over a broad range in chemical regimes. In addition, experience gained through this field deployment will allow the PI to further evaluate performance of the new TAG-AMS system. Results from this project will substantially improve our understanding of and ability to predict the chemical processing of biogenic gases to form particulate organic matter in the atmosphere, influences of this particulate material on clouds and precipitation fields, and resulting feedbacks on forests. This project will foster new collaborations involving the PI and other participants in the BEACHON-RoMBAS field campaign. Data interpretation will lever additional insight from measurements during the BEARPEX campaign. A postdoctoral researcher will be trained through the project and results will be integrated into classroom instruction by the PI. Knowledge gained by the PI, collaborating scientists, and students will be broadly disseminated through scholarly publications and will thereby contribute substantively to both the atmospheric chemistry and air quality communities.