CAREER: Quantifying the Isotopic Signature of Nitrogen Oxides Emissions Sources

该项目的重点是更好地了解向大气排放氮氧化物的来源。将从几个关键来源收集样品，如车辆、生物质燃烧和土壤产生的排放。将测量每份样本中的同位素氮（15 N）分数。这将使？指纹吗为大气层的每一个重要来源制定。能够确定氮氧化物的主要来源对大气的贡献，对于解决环境问题，如烟雾和酸雨的形成，以及空气质量建模和与源减少战略相关的决策具有广泛的意义。这项研究将与多方面的教育计划相结合，以增加少数族裔对科学研究的参与。已经开发出一种新方法，可以在收集样本时无需进行分馏的情况下测量氮氧化物（NOx）。 该方法使用NaOH与KMnO 4的溶液，其与气相中的NO和NO2反应，产生溶液中的硝酸盐。该方法已在PI中进行了测试？的实验室，并发现有一个良好的再现性水平的基础上重复测量的标准和样品。一个现场部署的系统正在开发配对这种技术的方法来确定同位素15 N的NOx的分数。 由此产生的氮氧化物来源的特性将使跟踪氮氧化物的来源，从城市污染的研究，生态系统中的氮肥。

This project focuses on developing a better understanding of the sources of nitrogen oxide emissions to the atmosphere. Samples will be collected from several key sources such as vehicles, biomass burning, and emissions generated from soils. The fraction of isotopic nitrogen (15N) will be measured in each sample. This will enable ?fingerprints? to be developed for each of the important sources to the atmosphere. Being able to identify the contribution of major sources of nitrogen oxides to the atmosphere has broad implications for addressing environmental issues, such as the formation of smog and acid rain, and for air quality modeling and decision making associated with source reduction strategies. This research will be integrated with a multi-faceted education program to increase the participation of minorities in science research.A new method has been developed to enable the measurement of nitrogen oxides (NOx) without having the samples subject to fractionation upon collection. The method uses a solution of NaOH with KMnO4 that reacts with both NO and NO2 in the gas phase yielding nitrate in solution. The method has been tested in the PI?s laboratory and found to have a good level of reproducibility based upon repeated measures of standards and samples. A field deployable system is being developed by pairing this technique with a method to determine the fraction of isotopic 15N of the NOx. The resulting characterization of NOx sources will enable tracing the sources of NOx for studies ranging from urban pollution to nitrogen fertilization in ecosystems.