Seasonal Measurements of Hydrogen Oxide Radical (HOx) Chemistry in Forests

该项目的目标是对不同森林环境中羟基自由基和过氧自由基的浓度进行更多的测量，以便对目前的大气化学模型进行可靠的测试。这些测量将在几个不同的森林环境中进行，包括印第安纳州大学研究和教学保护区附近的布卢明顿校园和PROPHET（氧化剂研究计划：光化学，排放和运输）塔网站在北方密歇根州。羟基自由基和过氧自由基控制着大气中许多重要痕量气体的寿命，如甲烷。羟基自由基反应还引发一氧化碳和挥发性有机化合物的氧化，在氮氧化物的存在下，可导致在大气中产生臭氧和二次气溶胶，即光化学烟雾的主要成分。准确了解这种化学性质对于评估控制策略和环境变化导致的排放变化对大气成分的影响非常重要。为了捕捉异戊二烯和其他生物源VOC排放影响大气的化学变化，将在季节转换期间进行测量，在春季叶片开花之前进行测量，然后持续到夏季。同时测量亚硝酸（HONO），这可能是一个重要的羟基自由基（OH）的来源，沿着总OH反应性的测量将进行，以量化自由基源和汇。将在森林树冠层的上方和下方进行测量，包括测量过氧自由基（RO 2）通量，为了提高我们对这些环境中自由基的源和汇的理解，并确定是否有明显的自由基在森林冠层之上和之下的传输，这项研究将作为大气化学和环境科学研究生跨学科培训的一部分学生此外，一个新开发的空气污染模块将实施印第安纳州大学的夏季经验，在可持续发展和环境营的高中生，重点是代表性不足的少数民族，第一代大学，和经济需要的学生。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

The goal of this project is to make additional measurements of the concentration of hydroxyl radical and peroxy radicals in different forest environments in order to provide robust tests of current models of atmospheric chemistry. These measurements will occur in several different forest environments, including the Indiana University Research and Teaching Preserve field lab near the Bloomington campus and the PROPHET (Program for Research on Oxidants: PHotochemistry, Emissions and Transport) tower site in northern Michigan. The hydroxyl radical and peroxy radicals control the lifetimes of many important trace gases in the atmosphere, such as methane. Hydroxyl radical reactions also initiate the oxidation of carbon monoxide and volatile organic compounds, that in the presence of nitrogen oxides can lead to the production of ozone and secondary aerosols in the atmosphere, the primary components of photochemical smog. An accurate understanding of this chemistry is important to assess the impact of changes in emissions as a result of control strategies and environmental change on the composition of the atmosphere.To capture the change in chemistry as isoprene and other biogenic VOCs emissions impact the atmosphere, measurements will be conducted during the seasonal transition, with the measurements conducted just prior to leaf bloom in the spring and continuing afterwards into the summer. Concurrent measurements of nitrous acid (HONO), which can be a significant source of hydroxyl radicals (OH), along with measurements of total OH reactivity will be made in order to quantify radical sources and sinks. Measurements will be made both above and below the forest canopy, including measurements of peroxy radical (RO2) fluxes, in order to improve our understanding of the sources and sinks of radicals in these environments and to determine whether there is significant transport of radicals above and below the forest canopy.The research will be used as a component of interdisciplinary training in atmospheric chemistry and environmental science for graduate students. In addition, a newly developed air pollution module will be implemented for Indiana University’s Summer Experience in Sustainability and the Environment camp for high school students, focusing on underrepresented minorities, first generation college, and financial need students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.