Measuring atmospheric microplastic composition and occurrence from an uncrewed aerial system

Airborne microplastic (MP) particles are transported through the atmosphere, yet direct measurements at altitude remain scarce. We developed a novel uncrewed aerial system (UAS)-based method for in situ MP sampling within and above the atmospheric boundary layer. In this proof-of-concept study, we deployed the UAS at 80–100 m above ground level (a.g.l.) in Colorado, USA, during fall 2024, collecting particles larger than 1 µm at two sites with high anthropogenic activity using an environmental cyclone sampler. Airborne particles were isolated, counted by optical microscopy, and identified by Raman microscopy with automated spectral analysis (OpenSpecy). Spectroscopically confirmed MPs were detected at 100 m a.g.l. and represented a mean of 13.8 ± 1.8% of the blank-corrected, morphologically selected airborne-particle counts for particles in the 3–10 µm size range. Hetero-aggregates dominated the samples, consistent with traffic-related material. This proof of concept demonstrates the feasibility of UAS-based atmospheric MP sampling and establishes a framework adaptable for ocean-surface, high-altitude, and remote environment monitoring.