Inorganic Additives Induce More Small-Sized Microplastics Releasing from Medical Face Masks

Although previous studies have extensively explored the release of microplastics from masks, the specific influence of inorganic additives on microplastic emissions has remained unidentified. Herein, we performed a comparative analysis of medical face masks (MFMs) with calcium carbonate (CaCO₃) additives against those devoid of CaCO₃ to understand their roles in microplastic release. Briefly, our investigation employed surface-enhanced Raman spectroscopy (SERS) to examine micro- and nanoplastic release, while the stereoscopic characterization of mixing states of additives in microplastic was accomplished through a simulated Raman scattering (SRS). We also pioneered a three-dimensional imaging (3D imaging) method for investigating the internal aging of plastic using SRS, which clearly revealed the link between inorganic additives inside polymers and photoaging. We found that inorganic additives substantially accelerate the photoaging of the plastic materials through multiple pathways and induce more small-sized microplastics. Follow-up radical quenching experiments confirmed carbonate radicals as the main cause of this phenomenon. Our research exposes the hazardous potential of inorganic additives in masks to amplify the emission of microplastics.