An early comparison of nano to microplastic mass in a remote catchment's atmospheric deposition

Abstract

The existence of nano sized plastic (NP) has been discussed heavily in recent years, however physical proof from environmental samples and direct comparisons to characterized microplastics is limited. Here we compare microplastic (MP) particles and counts (>10 µm) to NP particle (<0.45 µm) mass concentrations from deposition at a remote field site in the French Pyrenees (elevation 1425 m a.g.l.). Using Thermal Desorption – Proton Transfer Reaction – Mass Spectrometry (TD-PTR-MS) analysis, the data shows that NP is present in atmospheric deposition in quantities up to 2.0 × 105 nanograms m−2 day−1 (1.1 × 105 nanograms m−2 day−1 standard deviation), comparable to that of the >10µm microplastic (up to 1.1 × 105 nanograms m−2 day−1, 2.7 × 104 nanograms m−2 day−1 standard deviation). This comparison indicates the quantity of NP and MP may be similar in this atmospheric deposition, however the estimated particle count for NP is understandably multiple orders of magnitude greater compared to MP. Backward trajectory modelling was used to consider the transport of these MP and NP particles. This highlighted the extended spatial influence of NP and its propensity to remain elevated over a 7-day period.