Multiphase Chemistry in Soil and its Impact on Reactive Nitrogen Recycling

在这个由国家科学基金会化学部环境化学科学计划资助的项目中，印第安纳州大学的Jonathan Raff教授正在研究活性氮氧化物（NOy）气体如何与土壤表面相互作用。 NOy在燃料燃烧期间产生，并且是自由基的重要前体，自由基既控制污染物的寿命又产生有害的副产物（例如，臭氧和颗粒物）。通过吸附到土壤表面来去除NOy是一个很大程度上尚未探索的过程，尽管土壤是具有高反应性和高表面积的基质。 土壤包括地球表面的广大区域。其他活动包括为研究生（包括来自科学中代表性不足的群体的研究生）提供在环境化学科学中进行尖端和相关研究的机会。 Raff博士正在开发一项推广计划，为当地的初中和高中学生及其教师提供便携式污染物监测仪，用于实地考察和课堂实验。该研究的目标是研究NOy吸附到土壤上的速度以及将氮物种“循环”回大气的化学过程。在环境相关条件下，使用土壤化学，物理化学和生物化学技术的多相化学的几个NOy物种的各种土壤相关的基板进行了研究。这些活动的结果最终有助于更好地了解土壤中活性氮的命运，并保护人类健康免受空气质量差的影响。 随着地面臭氧的空气质量标准变得更加严格，受土壤排放和地面上NOy多相化学影响的NOy背景水平变得更加重要。动力学研究允许建模者更准确地参数化土壤NOy排放的化学传输模型。 这种模拟用于预测污染物的形成和移动，并为污染控制政策提供信息。

In this project, funded by the Environmental Chemical Sciences Program in the Division of Chemistry at the National Science Foundation, Professor Jonathan Raff of Indiana University is investigating how reactive nitrogen oxide (NOy) gases interact with soil surfaces. NOy is generated during fuel combustion and is an important precursor to the radicals that both control the lifetime of pollutants and generate harmful byproducts (e.g., ozone and particulate matter). Removal of NOy through adsorption to soil surfaces is a process that remains largely unexplored despite the fact that soil is a substrate with high reactivity and high surface area. Soil comprises vast areas of the Earth's surface. Additional activities include providing graduate students (including those from groups that are underrepresented in the science) with opportunities to perform cutting-edge and pertinent research in the environmental chemical sciences. Dr. Raff is developing an outreach program that provides local middle and high school students and their teachers with access to portable pollutant monitors for field trips and in-class experiments.The goal of the research is to study how fast NOy adsorbs onto soil and the chemical processes that "recycle" nitrogen species back into the atmosphere. The multiphase chemistry of several NOy species on a variety of soil-related substrates are studied under environmentally relevant conditions using soil chemistry, physical chemistry, and biochemistry techniques. Results from the activities ultimately contribute to an improved understanding of the fate of reactive nitrogen in soil and the protection of human health against poor air quality. As air quality standards for ground-level ozone become more strict, background levels of NOy that are influenced by soil emissions and multiphase chemistry of NOy on ground surfaces become more important. The kinetics studies allow modelers to more accurately parameterize soil NOy emissions in the chemical transport models. Such simulations are used to predict the formation and movement of pollutants and inform pollution control policy.