Probing nanoplastics derived from polypropylene face masks with hyperspectral dark-field microscopy

The high worldwide consumption of cheap plastic goods has already resulted in a serious environmental plastic pollu-tion, exacerbated by piling of disposed personal protective equipment because of the recent outbreak of COVID-19. The aim of this study was to assess the feasibility of dark -field hyperspectral microscopy in the 400-1000 wavelength range for detection of nanoplastics derived from weathered polypropylene masks. A surgical mask was separated to layers and exposed to UV radiation (254 nm) for 192 h. Oxidative degradation of the polypropylene was evidenced by ATR FT-IR analysis. UV treatment for 192 h resulted in generation of differently shaped micro-and nano-sized par-ticles, visualized by dark -field microscopy. The presence of nanoparticles was confirmed by AFM studies. The hyperspectral profiles (400-1000 nm) were collected after every 48 h of the UV treatment. The distinct hyperspectral features faded after prolonged UV exposure, but the assignment of some particles to either blue or white layers of mask could still be made based on spectral characteristics.

Automated summary

The high worldwide consumption of cheap plastic goods has led to a serious environmental plastic pollution, which has been exacerbated by the accumulation of disposed personal protective equipment during the COVID-19 outbreak. This study aimed to assess the feasibility of dark-field hyperspectral microscopy for detecting nanoplastics derived from weathered polypropylene masks in the 400-1000 wavelength range.