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项目资助的项目中，印第安纳大学的乔纳森·拉夫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是在燃料燃烧过程中产生的，是控制污染物寿命和产生有害副产品(例如臭氧和颗粒物)的自由基的重要前体。尽管土壤是具有高活性和高表面积的基质，但通过吸附到土壤表面去除NOY的过程在很大程度上仍未被探索。土壤由地球表面的大片区域组成。其他活动包括为研究生(包括那些在科学中代表性不足的群体)提供在环境化学科学方面进行尖端和相关研究的机会。拉夫博士正在开发一个推广项目，为当地的初中生和他们的老师提供便携式污染物监测仪，用于实地考察和课堂实验。这项研究的目标是研究氮氧化物在土壤中的吸收速度，以及将氮素重新循环到大气中的化学过程。利用土壤化学、物理化学和生物化学技术，在环境相关的条件下，研究了几种氮氧化物在各种土壤基质上的多相化学。这些活动的结果最终有助于更好地了解土壤中活性氮的去向，并保护人类健康免受恶劣空气质量的影响。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的多相化学影响的背景NOY水平变得更加重要。动力学研究使建模者能够更准确地在化学传输模型中对土壤NOY排放进行参数化。这种模拟被用来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.