Measurements of Tropospheric OH and HO2 Radicals in Forest Environments

该项目的总体目标是通过使用基于激光诱导荧光技术的新仪器测量森林环境中OH（羟基）和HO2（过氧化氢）自由基的浓度和化学性质，提高对生物排放对大气化学影响的认识。 该研究将侧重于测量OH和HO 2在不同的高度和附近的森林冠层的PROPHET（计划研究氧化剂：PHotochemistry，排放和运输）塔网站在北方密歇根州，以及AmeriFlux塔网站在中部印第安纳州。 这些测量将有助于确定是否未知的活性生物源排放物是一个重要的HOx（OH + HO2）自由基内的森林冠层在白天和晚上。 除了拟议的现场测量，实验室实验将进行各种生物挥发性有机化合物（VOCs）及其氧化产物，以更好地了解其氧化机制。该项目的更广泛的科学成果将是更好地了解生物排放对大气中臭氧和气溶胶形成的贡献，从而制定更有效的控制这些污染物的战略。 该项目还将为博士后助理、研究生和本科生，包括来自代表性不足群体的人提供研究和教育机会。 HOx仪器最终可能用于本科生和研究生实验室为基础的大气化学课程，让学生获得和分析痕量气体的环境测量，并通过发现体验科学的兴奋。

The overall goal of this project is to improve understanding of the influence of biogenic emissions on atmospheric chemistry through measurements of the concentrations and chemistry of OH (hydroxyl) and HO2 (hydroperoxyl) radicals in forested environments using a newly constructed instrument based on the technique of laser-induced fluorescence. The research will focus on measurements of OH and HO2 at various heights in and near the top of the forest canopy at both the PROPHET (Program for Research on Oxidants: PHotochemistry, Emissions and Transport) tower site in northern Michigan, as well as the AmeriFlux tower site in central Indiana. These measurements will help to determine whether unknown reactive biogenic emissions are a significant source of HOx (OH + HO2) radicals inside a forest canopy both during the day and at night. In addition to the proposed field measurements, laboratory experiments will be performed on various biogenic volatile organic compounds (VOCs) and their oxygenated products in order to better understand their oxidation mechanisms. The broader scientific results of this project will be an improved understanding of the contribution of biogenic emissions to ozone and aerosol formation in the atmosphere, leading to more effective control strategies for these pollutants. This project will also provide research and educational opportunities for postdoctoral associates, graduate students and undergraduates, including those from underrepresented groups. The HOx instrument may eventually be used in undergraduate and graduate laboratory-based atmospheric chemistry courses, allowing students to obtain and analyze ambient measurements of trace gases, and to experience the excitement of science through discovery.