Overlooked Emission of Polystyrene Nanoplastics through Sea Spray Aerosol

Abstract

The emission of nanoplastics through sea spray aerosol (SSA) from the ocean to the atmosphere has remained uncertain in different environments. The present study was intended to profile size-fractionated emission factors (EFs) of 100 nm polystyrene (PS) via SSA under different scenarios with surfactants and estimate the emission amounts of nano-PS from the North Atlantic. The EF of 100 nm PS in the synthetic seawater was 1700 ± 170. Fulvic acid reduced the emission of 100 nm PS, while Triton X-100 exhibited concentration-dependent effects on its release. The EFs in the synthetic seawater showed a unimodal peak at 1.0–1.8 μm. Fulvic acid and Triton X-100 shifted the peak size for EFs to 3.2–5.6 μm. The annual emission amount of nano-PS through SSA from the North Atlantic to the atmosphere was 135 000 t, accounting for 2% of the total budget in the mixed layer of the North Atlantic. The percentages would change to 0.8 and 2.8% with the presence of 0.1 mg L^–1 fulvic acid and 1 μg L^–1 Triton X-100, respectively. The present study documented the relative importance of emission of nanoplastics through SSA to their fate in the ocean and atmosphere.