Quantifying Airborne Micro- and Nanoplastics at the Aerosol Observatory of the University of Vienna

Understanding the atmospheric concentrations and properties of micro- and nano-plastics (MNPs) is essential to evaluate not only their sources, transport pathways and sinks, but also the effects they have on the environment, climate and human health. Especially as these effects are still largely unknown.

Here we present first results of atmospheric MNPs in PM2.5 (particulate matter with aerodynamic diameter < 2.5 μm) collected on filters at the Aerosol Observatory (35 m agl.) of the University of Vienna between 12.2024 and 12.2025. We aim to quantify the share of MNPs in PM2.5, their type and mass concentration over four seasons, and determine their sources (i.e. local versus long-range transport) by coupling observations with meteorological parameters, and FLEXPART Langrangian transport modelling.

In this study, daily PM2.5 filter samples are collected on quartz fibre filters using low volume filter sampler (SEQ47 50, Sven Leckel GmbH; 24 hr resolution) over a course of one year, and are subsequently analyzed with the thermal desorption – proton transfer reaction- mass spectrometer (TD-PTR-MS), for MNP mass concentration and chemical composition. The carbonaceous aerosol fractions (i.e. organic and elemental carbon) are analyzed using an offline thermo-optical method utilized by the Sunset Analyzer (Sunset Laboratory, Inc., USA) and follow the EUSAAR II protocol. Here we present the pilot results that focus on the analysis of the daily PM2.5 filter samples, as well as the preliminary results of the full-scale study that covers weekly pooled samples over the course of one year.

Preliminary results of the pilot study which covers ten daily PM2.5 filter samples with high (4.78-10.06 μg/m³) and low (~ 1 μg/m³) organic carbon loading show the presence of the following polymer types: polyethylene (PE), polyethylene telephtalate (PET), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PCV) and tire wear. High correlation (p<0.05) is found between the high organic carbon mass loading and the total mass of polymers detected.

These initial results highlight the presence of micro and nanoplastics in the urban air in Vienna and the importance of ensuring quantitative data to better understand their effects and transport pathways. Further, the results of this study are expected to complement the micro-FT-IR analysis of atmospheric particle deposition collected using wet and dry passive sampler at the Aerosol Observatory. Brought together, these measurements will provide a picture of micro- and nanoplastic occurrence across a size range from the nanoscale to hundreds of micrometres.