Hydrogen Peroxide Fluxes to Forest Canopies: Field & Laboratory Experiments

大气中的过氧化氢在对流层光化学和在云水中将二氧化硫转化为硫酸中起着重要作用，也可能对植被有毒。植物与大气过氧化氢之间的相互作用是大气科学界和植物科学界都感兴趣的问题。虽然对其向植被的干沉积速率进行量化是光化学模型所必需的，但很少有研究试图测量过氧化氢向植物的沉积。在以前的工作中已经证明，在现场和实验室实验中，以足够的精度测量过氧化氢以计算通量是可能的。在这项工作中，建议采用一种更直接的通量测量方法，即放松涡流积累（REA）方法，来测量森林冠层上的过氧化氢通量。然后，在三年的时间里，首席研究员将进行两种类型的实验：1)实地测量过氧化氢在森林冠层上的沉积速率；2)在森林研究中发现的代表某些相同物种的单个树苗上进行对照室实验。通过这两个实验，既可以量化实验环境条件下对冠层的沉积速率，又可以预测沉积速率随环境条件的变化情况。教育计划以三个主要目标为基础。与拟议的研究计划一样，教育计划强调环境研究的跨学科性质。计划开设本科和研究生课程，强调污染物的跨媒介行为，并利用包括化学、生物学、大气科学和工程学在内的几门科学。第二个目标是提高工程专业研究生和本科生的沟通技巧。第三个目标是提高学生的保留率，特别是来自代表性不足群体的学生。

9508417 Claiborn Atmospheric hydrogen peroxide plays important roles in tropospheric photochemistry and in converting sulfur dioxide to sulfuric acid in cloudwater, and may also be toxic to vegetation. The interactions between plants and atmospheric hydrogen peroxide are of interest to both the atmospheric and plant sciences communities. While quantification of its dry deposition rates to vegetation is necessary for photochemical models, there have been very few studies that have attempted to measure deposition of hydrogen peroxide to plants. In previous work it was demonstrated that it is possible, in both field and laboratory experiments, to measure hydrogen peroxide with adequate precision to enable calculation of fluxes. In this work, it is proposed to adapt a more direct measure of the flux, the relaxed eddy accumulation (REA) method, to measure hydrogen peroxide fluxes over a forest canopy. Then, over a three-year period, the principal investigator will conduct two types of experiments: 1) field measurements of deposition rates of hydrogen peroxide to forest canopies, and 2) controlled chamber experiments on individual saplings representing some of the same species found in the forest studies. By conducting both experiments, it will be possible to both quantify the deposition rate to the canopy under the environmental conditions of the experiment, and to predict how the deposition rate changes with changing environmental conditions. The education plan is based upon three main objectives. Like the proposed research plan, the education plan emphasizes the cross-disciplinary nature of environmental studies. Development of both undergraduate and graduate courses that emphasize the cross-media behavior of pollutants and that draw upon several sciences including chemistry, biology, atmospheric sciences, and engineering, is planned. The second objective is to improve communication skills of engineering students, both at the graduate and undergraduate levels. The third objective is to improve retention of students, particularly from underrepresented groups.