Understanding the Fate of Plastic Additives in Marine Aerosol Mimics

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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.