Collaborative Research: Organosulfate Multiphase Chemistry and Physicochemcal Properties--Oxidation and Sulfate Recycling in Aerosols and Cloud Droplets

该项目解决了在理解导致大气中颗粒有机硫酸盐形成的机械途径方面的一个空白。将进行实验室研究，以研究气态异戊二烯环氧二醇的去向，并研究这些反应的产物可能如何改变大气气溶胶的性质。这些研究的结果将有助于改善空气质量和气候模式中二次有机气溶胶形成的预测。本项目的目标包括：(1)异戊二烯环氧二醇(IEPOX)衍生的低挥发性颗粒有机硫酸盐(OSS)的非均相羟基自由基氧化，以了解相对湿度(RH)、预先存在的气溶胶成分(包括pH)和OH暴露如何改变白天OS的组成和物理化学性质；(2)IEPOX衍生OSS的非均相硝酸盐(NO3)氧化，以了解RH、先前存在的气溶胶成分(包括pH)和NO3暴露如何改变夜间OS组成和物理化学性质；和(3)云水氧化实验，以了解微粒IEPOX衍生的OSS如何循环无机硫酸盐以产生多功能OSS，从而在云滴蒸发时产生二次有机气溶胶(SOA)。该项目包括通过NSF资助的青年参与弹性科学计划和NIH资助的北卡罗来纳大学的21世纪环境健康学者计划以及通过密歇根大学的底特律研究实习和夏季体验(D-RISE)计划对高中生进行的外展努力。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 addresses a gap in the understanding of mechanistic pathways that lead to the formation of particulate organosulfates in the atmosphere. Laboratory studies will be conducted to examine the fate of gaseous isoprene epoxydiols and to study how the products of these reactions might alter the properties of atmospheric aerosol. The results of these studies will help to improve predictions of the formation of secondary organic aerosol in both air quality and climate models.The objectives of this project include the study of: (1) heterogeneous hydroxyl radical (OH) oxidation of isoprene epoxydiol- (IEPOX) derived low-volatility particulate organosulfates (OSs) to understand how relative humidity (RH), pre-existing aerosol composition (including pH), and OH exposure alter daytime OS composition and physicochemical properties; (2) heterogeneous nitrate (NO3) oxidation of IEPOX-derived OSs to understand how RH, pre-existing aerosol composition (including pH), and NO3 exposure alter nighttime OS composition and physicochemical properties; and (3) cloudwater oxidation experiments to understand how particulate IEPOX-derived OSs recycle inorganic sulfate to yield multifunctional OSs, and thus aqueous secondary organic aerosol (SOA) upon cloud droplet evaporation.This project includes outreach efforts to high school students through the NSF-funded Youth Engaging in the Science of Resilience Program and the NIH-funded 21st Century Environmental Health Scholars Program at the University of North Carolina and through the Detroit Research Internship and Summer Experience (D- RISE) program at the University of Michigan.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.