Microplastics deposited by snowfall in local and remote areas: a systematic review and meta-analysis.

Microplastics (MPs), as emerging contaminants, are transported to local and remote ecosystems via snowfall. This study constitutes first systematic review and meta-analysis of MPs deposited in snow, conducted in accordance with PRISMA guidelines, incorporating articles searched up to June 2025, and encompassing 28 studies with 472 snow samples. Results indicated that MP concentrations in local areas (97.7 MP/L) were approximately six times higher than those in remote areas (16.4 MP/L) (p < 0.001). Black and white were the predominant colors in remote and local regions, respectively; fibers dominated in local areas, while fragments prevailed in remote ones. Smaller particles (<500 μm) were more abundant in both local and remote sites. In terms of polymer types, acrylates were more common in local areas, while polyurethane predominated in remote areas. These differences reflect the influence of local anthropogenic sources and selective atmospheric transport of MPs. The findings underscore the threats to sensitive ecosystems, the exacerbation of climate change, and associated health risks. Recommendations include standardization of methodologies, concurrent local-remote sampling guided by wind patterns, and increased attention to contaminants adsorbed onto MPs.