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

•Comparable micro and nanoplastic assessment is vital to advancing source-transport-fate assessments.•There are effective methods to compare atmospheric micro and nanoplastics.•Comparative analysis suggests order of magnitude greater nanoplastic particles in the atmosphere.•Nanoplastics are transported further and across a greater altitude range.•Tentative global source assessment of atmospheric micro(nano)plastics. 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 (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. [Display omitted]