Plastics are ubiquitous in the world’s oceans and recent work indicates micro- and nano-plastics can get transferred from the ocean to the atmosphere in sea spray aerosol (SSA). In addition to the primary plastics, hazardous chemical residues including organic ultraviolet (UV) filters, hardeners, and antimicrobial compounds, which can represent a sizable fraction of plastics, may become airborne in SSA and pose an unknown risk to public health. However, their existence in SSA has never been confirmed. In this work, I will present our findings on (1) quantified plastic residue species and other hazardous chemical contaminants measured in coastal aerosol in San Diego, CA and their connections to SSA, and (2) laboratory studies on the heterogeneous and photochemical oxidative degradation of plastic residues in SSA-mimicking aerosols comprised of inorganic sea salts and photosensitizing organic molecules. We find that some plastic residues selectively transfer in SSA. In the presence of NaCl and photosensitizing organic molecules, plastic residue species following heterogeneous reaction with OH radicals can decay at a rate twice as fast as the pure-component species. The enhanced degradation is attributed to enhanced production of Cl radicals driven by reactions between OH and excited-state photosensitizing molecules with Cl-. This work has important implications for understanding pollutant transport and exposure risks in coastal marine environments.<b> </b>

Quantifying the emissions and oxidative decay of plastic residues in marine aerosol matrices

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