Piotr Markuszewski

Microplastics are now recognised as contaminants of both the marine environment and the atmosphere, yet the processes governing their exchange across the air–sea interface remain poorly understood. This presentation will showcase results from field studies conducted in the Baltic Sea and the northern Indian Ocean, with a focus on how ambient meteorological and oceanographic conditions control the occurrence, properties, transport, release, and uptake of airborne and marine microplastics. The talk will highlight how microplastic concentrations, composition, and size distributions change across contrasting environments and under different forcing conditions. Results from the Baltic Sea reveal a strong coupling between the sea surface and the atmosphere, with evidence of both marine emission and atmospheric transport of microplastics. Observations collected during major winter storms in 2022 further demonstrate the importance of hydrodynamic forcing for the redistribution of microplastics within the water column. In contrast, measurements from the Maldives indicate weaker air–sea coupling during the observation period, with airborne microplastics linked more closely to regional polluted air-mass transport than to local marine emissions. By combining microplastic measurements with atmospheric aerosol observations, this presentation will underline the importance of an interdisciplinary air–sea interaction framework for understanding the environmental fate of microplastics. More broadly, it will demonstrate the research potential of integrating aerosol physics, marine observations, and process-based interpretation to investigate emerging pollutants in the coupled ocean–atmosphere system.