How High Are PFAS Levels in Facemasks?

Per- and polyfluoroalkyl substances (PFAS) are organofluorine compounds that contain at least one perfluorinated methyl group (–CF₃) or perfluorinated methylene group (–CF₂–). There are thousands of different PFAS, and they are widely used in a variety of products. PFAS persist in the environment and are also known colloquially as “forever chemicals”. There are health and environmental concerns associated with PFAS.

PFAS can, for example, be used to repel fluids. Thus, some companies could be adding PFAS coatings to their facemasks. During the pandemic, people have been wearing facemasks for long periods, which could expose them to PFAS through inhalation or skin exposure. In addition, PFAS from discarded facemasks might pollute the environment. However, the levels of PFAS in facemasks had not been thoroughly studied so far.

Ivan A. Titaley, Oregon State University, Corvallis, USA, and colleagues have measured PFAS levels in different types of face masks and analyzed the implications for human exposure and the environment. The team used mass spectrometry (MS) to measure nonvolatile and volatile PFAS in nine types of face masks: one surgical mask, one N95 mask, six reusable cloth masks, and a heat-resistant fabric mask advertised to firefighters. Nonvolatile PFAS were found in all facemasks, and volatile PFAS were found in five facemasks. The surgical and N95 masks showed the lowest levels, and the firefighting mask had the highest levels.

The researchers estimated the exposure to PFAS for children and adults based on wearing a mask for 10 h per day. According to their calculations, regular wear of the surgical, N95, and cloth masks would not pose a risk. However, the higher PFAS levels in the firefighter mask exceeded the dose considered safe when worn for a full day at higher activity levels. Thus, masks treated with high levels of PFAS worn for extended periods of time might be a notable source of exposure.

The team also analyzed the environmental impact of PFAS from surgical and N95 masks, which are most commonly discarded in landfills. They estimated that masks should be only a minor source of PFAS in landfill leachates, even in scenarios where large numbers of masks are discarded and most of the PFAS leach out of them.