CAREER: Revitalizing aerosol-cloud-chemistry research at Whiteface Mountain

在纽约州的白面山（WFM）山顶研究观测站提出了一种新的测量策略，该策略将能够更完整地描述云内发生的化学过程。自20世纪70年代中期以来，在WFM进行了多相化学观测，当时人们对气相二氧化硫排放转化为气溶胶硫酸盐产生酸雨特别感兴趣。随着联邦和地区空气质量标准的实施，该地区云层中的化学物质发生了实质性的变化。这些变化表明出现了一种以有机物和铵为主的新化学体系。这个项目正在研究这种变化的化学机制。这项工作的中心假设是，云处理继续改变美国东北部环境气溶胶的化学成分，其方式与过去几十年主要的无机过程根本不同。更具体地说，云处理通过可溶有机气体的冷凝和随后的水反应增加了二次有机气溶胶质量，产生较少的挥发性有机化合物，这些化合物在液滴蒸发时仍处于冷凝相。本研究将探讨以下科学问题：(1)WFM水体水溶性有机碳（WSOC）增加趋势的驱动因素是什么？(2)当云滴蒸发时，多余的氨和WSOC蒸汽会发生什么变化？(3)过量氨的增加是否会导致未来WSOC的增加？拟议的研究将建立在WFM过去和正在进行的研究的基础上，并使人们更好地了解云内发生的多相化学过程。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。

A new measurement strategy is proposed at the Whiteface Mountain (WFM) summit research observatory in New York State that will enable a more complete characterization of the chemical processes occurring within the clouds. Multiphase chemical observations have been made at WFM since the mid-1970s, when there was particular interest in the conversion of gas-phase sulfur dioxide emissions to aerosol sulfate resulting in acidic rain. Subsequent to the implementation of federal and regional air quality standards, the chemistry occurring within the clouds at this location has changed substantially. These changes suggest the emergence of a new chemical regime dominated by organics and ammonium. This project is investigating this changing chemical regime.The central hypothesis of the proposed work is that cloud processing continues to alter the chemical composition of ambient aerosols in the northeastern U.S., in ways that fundamentally differ from the dominant inorganic processes in previous decades. More specifically, cloud processing increases secondary organic aerosol mass via condensation of soluble organic gases and subsequent aqueous reactions, yielding less volatile organic compounds that remain in the condensed phase upon droplet evaporation. The proposed research will investigate the following science questions: (1) What is driving the increasing trend in water soluble organic carbon (WSOC) at WFM? (2) What happens to the excess ammonia and WSOC vapor when the cloud droplets evaporate? and (3) Will increases in excess ammonia lead to increased WSOC in the future? The proposed research will build upon past and ongoing research at WFM and lead to a better understanding of multiphase chemical processes occurring within clouds.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.