The Importance of Organic Nitrates as Sinks for Atmospheric Nitrogen Oxides

小行星9520374 该项目旨在提高我们对有机硝酸盐对对流层臭氧的产生和分布的影响的认识。有机硝酸盐在有机过氧自由基与一氧化氮之间的反应中产生，通常作为次要产物。该反应通道的重要性随着有机前体的尺寸而增加。通过该反应去除一氧化氮可以构成重要的NOx吸收器，从而降低臭氧形成速率。为了准确模拟臭氧收支，需要天然烃氧化途径中有机硝酸盐的产率。在该项目中，异戊二烯、萜烯和芳烃形成硝酸盐的产量将使用一个大型光化学反应室进行测量，该反应室配备有能够区分单个硝酸盐物种的取样和检测装置。 此外，将在密歇根州南部半岛西北端的一个森林地区进行有机硝酸盐的环境测量，使用吸附剂浓度和荧光检测的独特组合，使调查人员能够测量气相和颗粒相有机硝酸盐的总浓度，检测限很低。这些数据将是有用的对流层臭氧的建模研究，并将提供新的见解的问题，大气中的总活性氮（NOy）的形态，以及有机硝酸盐作为汇和/或车辆运输大气中的NOx的重要性。

9520374 Shepson This project aims at improving our understanding of the impact of organic nitrates on the production and distribution of tropospheric ozone. Organic nitrates are produced in the reaction between organic peroxy radicals with nitric oxide, usually as a minor product. The importance of this reaction channel increases with the size of the organic precursor. Removal of nitric oxide through this reaction could constitute an important NOx sink, thus reducing the ozone formation rate. In order to accurately model the ozone budget, the yields of organic nitrates in the oxidation pathways of natural hydrocarbons are needed. In this project, the yield of nitrate formation from isoprene, terpenes, and aromatic hydrocarbons will be measured using a large photochemical reaction chamber equipped with sampling and detection devices capable of distinguishing individual nitrate species. In addition, ambient measurements of organic nitrates will be conducted at a forested site at the northwestern tip of the Michigan southern Peninsula, using a unique combination of adsorbent concentration and chemiluminescent detection that will enable the investigators to measure the total concentration of both gas- and particulate-phase organic nitrates with very low limits of detection. These data will be useful for modeling studies of tropospheric ozone, and will provide new insights into the problem of the speciation of atmospheric total reactive nitrogen (NOy), and the importance of organic nitrates as a sink and/or vehicle for the transport of atmospheric NOx.