Quantifying Natural and Anthropogenic Influences on Nitrogen Oxides Emissions and Chemistry

该项目预计将有助于更好地了解自然和人类活动对大气氮氧化物(NOx)氧化化学的影响，以及它将对氮的生物地球化学循环和气候产生什么影响。该项目有以下目标：(1)量化火山喷发与氧化化学和活性氮排放的相互作用；(2)评估自然气候变化，特别是小冰期对北半球中纬度地区大气氧化化学的影响；(3)研究人类活动对氧化化学和活性氮排放的影响。这项研究将分析保存在中纬度冰川冰芯中的硝酸盐，以提供过去中纬度大气成分的独特、长期记录。将从上弗里蒙特冰芯提取硝酸盐的稳定同位素，通过大气中的NOx氧化形成，以重建自公元1700年左右以来NOx氧化化学和排放源的变化。通过分析关键的氧和氮的稳定同位素，以大约每年的分辨率，将产生第一个全面的，超过100年的记录，来自美国毗邻的中纬度冰川。该项目将支持一名早期职业科学家，并为研究生的培训做出贡献。该项目团队还将参与南卡罗来纳大学的ACS SEED项目，该项目为贫困高中生提供科学研究经验。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project is expected to lead to a better understanding of how atmospheric nitrogen oxides (NOx) oxidation chemistry is influenced by natural and human activities and what impact it will have on nitrogen biogeochemical cycling and climate. The project's findings will inform predictive models for NOx emissions and oxidation under changing climate conditions.The project has the following objectives: (1) Quantify the interplay of volcanic eruptions with oxidation chemistry and reactive nitrogen emissions; (2) Assess the influence of natural climate change, specifically the Little Ice Age, on atmospheric oxidation chemistry within the northern hemisphere mid-latitudes; (3) Examine the influence of human-induced activities on oxidation chemistry and reactive nitrogen emissions. The study will analyze nitrate preserved in an ice core in a mid-latitude glacier to provide a unique, long-term record of past mid-latitude atmospheric composition. The stable isotopes of nitrate, formed via NOx oxidation in the atmosphere, will be extracted from the Upper Fremont Glacier ice core to reconstruct changes in NOx oxidation chemistry and emission sources since circa 1700 A.D. By analyzing key stable isotopes of oxygen and nitrogen with approximately annual resolution, the first comprehensive, over 100-year record from a mid-latitude glacier in the contiguous U.S. will be produced.This project will support an early-career scientist and contribute to the training of a graduate student. The project team also will participate in the ACS Seed Program at the University of South Carolina, that provides science research experience to underprivileged high school students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.