Emission through sea spray aerosol (SSA) is considered as an important pathway of microplastics from the ocean to the atmosphere. Microplastics could fragment into nanoplastics (NPs) under UV irradiation, water motion, and wind in the ocean.  If the amounts of NPs transported with SSA into the atmosphere are overlooked, the extent of plastic pollution in the atmosphere would be underestimated. Therefore, 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 metric tons, accounting for 2% of 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.
 

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