Novel Single-Particle Analytical Technique for Inhalable Airborne Microplastic Particles by the Combined Use of Fluorescence Microscopy, Raman Microspectrometry, and SEM/EDX

초록

This study presentsa novel and efficient method foranalyzing inhalable airborne microplastics (AMPs) in ambient PM10 aerosols. Although many studies have been conducted on MPsin a variety of environments, the physicochemical characteristicsof AMPs of inhalable size (<10 mu m) in ambient PM10 are poorly understood because of the lack of suitable analyticalmethods. The method employed in this study combines fluorescence microscopy,Raman microspectrometry (RMS), and scanning electron microscopy/energy-dispersiveX-ray spectrometry (SEM/EDX) for an efficient and reliable investigationof inhalable AMPs, which constitute a small portion of ambient PM10 aerosol particles. Fluorescence microscopy and stainingare used to select particles with high MP potential from ambient urbanPM(10) aerosols. The combination of RMS and SEM/EDX thenallows for a detailed characterization of these particles on a single-particlebasis. The results of the study show that similar to 0.008% of the particlescollected using a PM10 sampler had high MP potential, correspondingto similar to 800 particles/m(3). Among the stained particlesof <10 mu m, 27% were determined to be plastic, while the remaining73% were found to be from tire/road wear. The number of inhalableAMPs was estimated to be 192 (+/- 127) particles/m(3).This study provides an important insight into the characteristicsof inhalable AMPs in ambient PM10 aerosols that are particularlycritical in respect of human health and climate change. The authorshighlight that the use of a single fluorescence staining method canoverestimate the number of inhalable AMPs in ambient air by includingtire/road wear particles. To the best of their knowledge, this isthe first study to demonstrate the morphological and spectroscopiccharacteristics of the same individual inhalable AMPs.

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