Evaluating the Atmospheric Dynamics of Nitrate and Sulfate in Southern New England in Response to Emission Regulations

在过去的几十年里，大气中硝酸盐和硫酸盐颗粒的浓度显著下降，然而，控制它们从排放的前体气体中产生的过程仍然不明确。该项目旨在通过化学和同位素分析2005年至2018年在新英格兰南部不同地点收集的储存过滤器样本来填补这一知识空白。通过这项研究获得的13年记录将有助于为包括大气化学、生态学、健康、气候和政策在内的各个领域提供信息。该项目旨在利用浓度和同位素组成的独特组合来帮助限制硝酸盐和硫酸盐形成的大气机制。存档的过滤器将提供一段时间的季节性记录，在这段时间内，氮氧化物和二氧化硫气体的排放显著下降，导致了相关的硝酸盐和硫酸盐颗粒的非线性减少。非线性的原因是通过使用稳定同位素的分选(i)氮和硫的指纹识别和排放源的源分配，以及（ii）氧的生产途径为硝酸盐和硫酸盐提供信息。这项工作产生的新数据将通过推断生态系统和全球气候的趋势，影响大气化学以外的领域。PI团队将与不同设施的工作人员合作，并指导一名研究生和几名本科生完成这项劳动密集型的分析研究。结果还将纳入大气化学课程，并在当地小学的年度推广活动中分享。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Atmospheric particulate nitrate and sulfate concentrations have decreased significantly during the last decades, yet, the processes that control their production from emitted precursor gases remain ill-defined. The project seeks to fill this knowledge gap by chemically and isotopically analyzing stored filter samples collected between 2005 and 2018 at various locations in southern New England. The 13-year record obtained through this study will help inform diverse fields including atmospheric chemistry, ecology, health, climate and policy. The project aims at using a unique combination of concentration and isotopic compositions to help constrain atmospheric mechanisms of nitrate and sulfate formation. Archived filters will provide a seasonal record that spans a period during which significant declines in emission of nitrogen oxide and sulfur dioxide gases have led to associated, albeit non-linear decreases in particulate nitrate and sulfate. The cause for non-linearity is investigated by using fractionation of stable isotopes of (i) nitrogen and sulfur for fingerprinting and source apportionment of emission sources, and (ii) oxygen to inform production pathways for nitrate and sulfate. Novel data generated from this work will impact fields beyond atmospheric chemistry by inferring trends in ecological systems and global climate. The PI team will work with staff at various facilities and supervise one graduate and several undergraduate students to complete this labor-intensive analytical study. Results will also be incorporated into the atmospheric chemistry curriculum and shared in an annual outreach event for local elementary schools.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.