Phthalate Transfer and Enrichment in Artificial Sea Spray Aerosols

MOLLY HEDIN, Kanuri Roundtree, Diana Tran, Maya Morris, Xitlali Ventura, Jonathan Slade, University of California, San Diego

     Abstract Number: 462
     Working Group: Aerosol Chemistry

Abstract
Phthalates (Phthalate Acid Esters; PAEs) are widely used toxic plasticizers, acting as binding agents in everyday products. Their contamination in our environment is widespread, and previous studies have identified the air-sea exchange of PAEs in many major oceans around the world. The enrichment and transfer specifics of PAEs in the aerosol phase occurring at the air-sea interface remain unknown. The transfer of PAEs from the ocean to the aerosol phase includes mechanisms of bubble bursting and wave breaking. To simulate ocean conditions, a Marine Aerosol Reference Tank (MART) is used to study the enrichment and air-sea transfer of PAEs. Artificial seawater at a salinity of 35 ppt, and a sea surface microlayer (SML) of palmitic acid (PA) at a concentration of 35µM, were used to mimic ocean conditions. Three different PAEs found in previous field studies were applied to the surface of the artificial ocean matrix at environmentally relevant concentrations, around 3ng/L; Dimethyl phthalate (DMP), Dibutyl phthalate (DBP), and Di(2-ethylhexyl) phthalate (DEHP) were used as they range in carbon chain length and bulk. Aerosols generated from the MART were collected on quartz fiber filters with a pore size of one micron. The particles are pushed through a flow of purified air, with the relative humidity and temperature measured via a Vaisala probe, and a size distribution via a scanning electrical mobility sizer. The concentration of PAEs on collected aerosol filters, in the SML extracted via a glass sheet, and bulk seawater samples were determined by GC-MS. Using this data, enrichment factors with respect to Na+ for PAE aerosol transfer were obtained. This work provides insight into how PAEs enter the atmosphere, their potential effects on air pollution, and a greater understanding of their environmental impact in the marine boundary layer.