Understanding the Fate of Plastic Additives in Marine Aerosol Mimics

该项目包括大气反应动力学的实验室研究以及有毒化学添加剂对塑料的化学和物理转化（例如，增塑剂、抗菌剂和紫外线过滤剂）。这些添加剂通常最终进入海洋，在那里它们可以渗入周围的水中，在海洋表面微层中富集。在那里，它们可以作为海洋环境中的气溶胶成分通过空气传播，并传播很长距离，成为人类接触的可呼吸途径，并影响顺风地区的空气质量。以下科学问题将得到解决：（1）塑料添加剂在气溶胶相中与羟基自由基（OH）的非均相反应的化学寿命是多少？(2)颗粒组成如何相对于无机离子的浓度（例如，氯化钠），有机物，并存在光敏溶解有机物（DOM）的影响OH反应吸收和降解动力学的塑料添加剂在气溶胶阶段？(3)在没有OH的情况下，海洋相关的光敏DOM在可见光/紫外线照射下是否会降解气溶胶相塑料添加剂，它是否与非均相氧化竞争，以及主要的光敏化途径是什么？(4)气态半挥发性紫外线过滤剂在气相中氧化产生可感知的二次有机气溶胶吗？该奖项反映了NSF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。

This project includes laboratory investigations of the atmospheric reaction kinetics and the chemical and physical transformations of toxic chemical additives to plastics (e.g., plasticizers, antimicrobials, and UV filters) in the environment. These additives often end up in the oceans where they can leach into the surrounding water, becoming enriched in the sea surface microlayer. There they can become airborne as components of aerosol in the marine environment and travel long distances, serving as a respirable pathway for human exposure and impacting air quality in downwind regions. The following scientific questions will be addressed: (1) What are the chemical lifetimes of plastic additives in the aerosol phase with respect to heterogeneous reactions with hydroxyl radical (OH)? (2) How does particle composition, with respect to concentrations of inorganic ions (e.g., NaCl), organic matter, and presence of photosensitizing dissolved organic matter (DOM) influence OH reactive uptake and degradation kinetics of plastic additives in the aerosol phase? (3) Does addition of marine-relevant photosensitizing DOM degrade aerosol-phase plastic additives upon visible/UV irradiation in the absence of OH, is it competitive with heterogeneous oxidation, and what are the dominant photosensitized pathways? (4) Do gaseous semi-volatile UV filters oxidize in the gas phase to produce appreciable secondary organic aerosol?This effort and includes support and training for a postdoctoral researcher.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.