Atmospheric contribution of nanoplastics to North Atlantic Ocean

Nanoplastics (d ≤ 1 µm) are now recognized as ubiquitous contaminants throughout the Earth system. However, the mechanisms governing their transport and exchange between environmental compartments remain poorly constrained. Although elevated concentrations of nanoplastics have been reported in the North Atlantic Ocean, their dominant sources and transport pathways still require clarification. Marine nanoplastics may originate from the fragmentation and physicochemical degradation of larger plastic debris entering the ocean, but atmospheric transport and dry deposition represent an additional, potentially important pathway supplying nanoplastics to remote oceanic regions. In this study, thermal desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS), coupled with multicomponent multivariate standard addition (MMSA), was applied to quantify nanoplastics collected on aerosol filters during a research expedition across the North Atlantic Ocean from Vigo, Spain, to the Bahamas in November–December 2023. Nanoplastics from five major polymer classes—polystyrene (PS), polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), and polyethylene terephthalate (PET)—were detected in all air samples. The results reveal substantially higher nanoplastic concentrations in air masses influenced by continental sources, with a pronounced decrease over the mid-Atlantic region. Concentrations ranged from 2.01 to 11.69 ng m⁻³ for PS, 7.12 to 59.71 ng m⁻³ for PVC, 9.94 to 50.91 ng m⁻³ for PE, 6.99 to 44.77 ng m⁻³ for PP, and 10.54 to 35.31 ng m⁻³ for PET.These findings demonstrate that atmospheric transport plays a central role in controlling the distribution of nanoplastics over the North Atlantic and constitutes a major pathway linking terrestrial plastic emissions to the remote ocean.