High debit sampling of airborne micro and nanoplastics in remote sea

The occurrence of micro and nano plastics has been reported in every environmental compartment including marine and freshwaters, soils and sediments, air and atmospheric precipitations.  Recent evidence showing the presence of airborne microplastics in remote ecosystems highlights the extent of this pollution. The atmospheric transportation and the distribution of airborne microplastics still need to be better documented to understand the dynamic of microplastic transfer between ecosystems.

While most studies dedicated to the analysis of microplastics in the air use a passive sampling methodology through atmospheric deposition we developed an original stainless device to sample large volumes of air with high debit (2000 L/min) providing a fast sampling of aerosols within a small localized area. An optimized sampling protocol has been deployed in the North Western Mediterranean Sea from the Expedition 7th Continent (E7C) boat. 19 sampling sites have been studied during the E7C expedition in September-October 2019, including measurements in port and coastal areas as well as offshore environments. The analysis of micro/nano plastics was carried out using pyrolysis coupled with gas chromatography and tandem mass spectrometry (Py-GC-MS/MS). This approach allowed us to evaluate the concentrations of micro and nano plastics present in the samples for 5 types of plastics (polypropylene, polystyrene, polymethyl methacrylate, polyethylene terephthalate and polycarbonate) and for 2 size ranges (5-50μm and <5μm).

This study confirmed that plastic particles are present in the atmosphere even in remote areas such as the offshore environments. The results showed that airborne micro and nano plastics were detected at each sampling station, from the coast to the open sea, at various concentrations. Py-GC-MS/MS analysis allowed us to quantify the 5 types of polymer and revealed the predominance of PET and PP material. High-volume samplers and  Py-GC-MS/MS analysis have proven to be an efficient and powerful methodology to gather and quantify airborne plastic particles at micro and nanoscale level.