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

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 mi-croplastic (MP) particles and counts ( > 10 & mu;m) to NP particle ( < 0.45 & mu;m) 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 x 10 5 nanograms m- 2 day- 1 (1.1 x 10 5 nanograms m- 2 day- 1 standard deviation), compa-rable to that of the > 10 & mu;m microplastic (up to 1.1 x 10 5 nanograms m- 2 day- 1, 2.7 x 10 4 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.

Automated summary

The existence of nano-sized plastic (NP) has been widely discussed in recent years, but there is limited physical evidence and direct comparison to microplastics. This study compared microplastic (MP) particles and counts (>10 μm) to nano-sized plastic particle (<0.45 μm) mass concentrations from atmospheric deposition in the French Pyrenees. The results showed that the quantity of nano-sized plastic may be similar to microplastics in this atmospheric deposition, but the particle count for nano-sized plastic is significantly higher. Backward trajectory modeling indicated the extended spatial influence and elevated levels of nano-sized plastic over a 7-day period.