Over the past two decades, microplastics (MPs) and nanoplastics (NPs) have been recognized as emerging pollutants, detected across every environmental compartment of the Earth's system—the atmosphere, hydrosphere, lithosphere, and biosphere.
Their pervasive presence has drawn increasing attention from researchers focused on biogeochemical cycles and climate change. Significant gaps remain, however, in quantifying the stocks, sources, transformation, and fate of plastics, especially within the atmosphere, primarily due to analytical limitations in detecting and characterizing particles across micro- to nanoscale dimensions.
To address these challenges, a research team from the Institute of Earth Environment of the Chinese Academy of Sciences (IEECAS) developed a semi-automated microanalytical method to quantify atmospheric plastic particles and their cross-compartmental fluxes—airborne, dustfall, rain, snow, and dust resuspension—in two major Chinese megacities: Guangzhou and Xi'an.
By using a computer-controlled scanning electron microscopy system, which minimizes human bias compared to conventional manual inspections, the team detected plastic concentrations in total suspended particulates (TSP) and dustfall fluxes that are two–six orders of magnitude higher than those reported by visual identification techniques (e.g., manual SEM-EDX, μ-FTIR, or μ-Raman).
Additionally, estimated fluxes of MPs and NPs varied by two–five orders of magnitude across key atmospheric compartments, driven largely by roaddust resuspension and wet deposition. Furthermore, deposition samples contained more heterogeneously mixed plastic particles than aerosol and resuspension samples, indicating enhanced particle aggregation and removal during atmospheric transport.
This study marks the first detection of NPs as small as 200 nm in complex environmental matrices. It provides a quantitative assessment of atmospheric plastics, the least understood reservoir in the global plastic cycle, and delivers new insights into their environmental transformation, fate, and broader implications for climate dynamics, ecosystem integrity, and human health.
These findings were published in Science Advances on January 7.
