Simultaneous trace mass and quantity of airborne microplastics based on electromagnetic heating-pyrolysis-mass spectrometry, taking surgical face masks as an example

Microplastics (MPs) in the atmosphere have attracted global concern due to their potential threats to human health. However, the current rapid analytical method for airborne MPs is insufficient, which hinders a comprehensive understanding of their environmental risks. In recent years, the disposable face masks have emerged as a new source of airborne MPs. There are significant knowledge gaps regarding MPs from mask, including detection methods, formation mechanisms, and environmental abundance. This study presented a novel analytical approach for the rapid detection of airborne MPs using the electromagnetic heating-pyrolysis-mass spectrometry (Eh-Py-MS). To validate this method, surgical face masks were employed as an illustrative example. The mass-related quantification of MPs was realized based on the Eh-Py-MS. By employing a conversion model of mass, size, and density, simultaneous assessment of both mass and quantity of MPs was realized. The recovery rates were in the range of 86.6%–111.6% and the precision (RSD) was 8.4%, which was sufficient for rapid quantification. Results showed that the simultaneous tracing of mass and quantity of airborne microplastics could be successfully achieved through the developed method. Furthermore, the formation mechanism of MPs in surgical masks under UV exposure was also investigated to address the knowledge gap of masks MPs. Results indicated that surgical masks could be a neglected source of airborne microplastics in the environment. This study aims to provide valuable insights for the rapid assessment of airborne MPs in the environment.