Atmospheric Microplastic in the Arctic and Mainland Norway; comparing urban and remote locations 

The majority of studies on the transport of microplastics to the Arctic have focused on ocean pathways. Ocean currents originating in the south of Europe have been proposed to function as major transport routes, carrying microplastics from the more densely populated southern areas in Europe to the Arctic (Cózar et al., 2017; Tekman et al. 2020). However, given the limited empirical data and lack of harmonized methodologies for sample collection, it is not yet possible to estimate the magnitude, composition and sources of atmospheric microplastics transported to the Arctic. Here we present the outcomes of a study applying passive and active air-samplers for wet and dry deposition on two remote monitoring stations, Ny Ålesund (Svalbard) in the High Norwegian Arctic, and at Birkenes in mainland Norway in 2022 and 2023. We complement the results with active airsamples collected on cruises along the East- and Westcoast of Svalbard in 2021 and 2023, representing Arctic offshore samples. Deposition sampling at Norwegian urban sites were carried out to further our understanding on sources and emission volumes from high populated areas. Results were further analysed with respect to their spatial origin and long-range transport using the Lagrangian particle dispersion model FLEXPART. Rubber from car tires and Nylon dominated most samples, followed by PMMA and PVC. The estimated concentrations were fitting well on most timepoints, with some underestimation, indicating some missing sources in the model. Bi-weekly samples were collected during the period of June-December in 2022 and 2023 for the Norwegian onshore samples and during June 2021 and 2023 for the arctic offshore samples. We used full metal bulk precipitation samplers and suspended air samplers (Innovation NILU’s Atmospheric Microplastic Collector). All samples were handled under strict QA/QC requirements, with all sample treatment occurring in controlled conditions of clean rooms and laminar flow cabinets. After filtration on a GF/F filter, polymer determination was performed by pyr-GC/MS (Frontier lab multi shot pyrolizer EGA/PY 3030D connected to a Frontier lab AS 1020E Auto shot sampler connected to a ThermoScience TSQ9000 GC/MS/MS). All samples were accompanied with field and procedural blanks. Results were further analysed with respect to their spatial origin and long-range transport using the Lagrangian particle dispersion model FLEXPART. Rubber from car tires and Nylon dominated most samples, followed by PMMA and PVC. The estimated concentrations were fitting well on most timepoints, with some underestimation, indicating some missing sources in the model. While SBR and Nylon dominate in the Norwegian mainland samples, contribute almost every of the measured polymers to the samples from Zeppelin. These differences can be explained by the closeness to urban regions being a source of car tire particles and synthetic textiles for Birkenes in Southern Norway, while Zeppelin is rather impacted by Long-range-transport of a broad range of polymers. MP concentrations in deposition samples were more than 10000-times higher than in active samples, and Arctic samples were in general lower than samples from the Norwegian mainland.