The use of face masks to reduce inhalation exposure to reactive disinfectants

Following the COVID-19 pandemic, the use of face masks has become a “new norm” to avoid contagion. Although masks are effective in reducing aerosol transmission, including that of virus particles, studies on the effect of face masks on inhalation exposure to toxic substances are scarce. This study first reports that wearing fabric face masks reduces the inhalation of reactive chlorine gas generated from chlorine disinfectants. Effective chlorine concentrations both inside and outside masks while using a consumer product were compared quantitatively by two methods: real-time measurement using proton transfer reaction time-of-flight mass spectrometry and time-weighted average exposure concentration measured by passive air sampling. Chlorine gas levels within masks were significantly lower than those outside masks; this reduction was not as apparent for the two representative volatile organic compounds, ethylbenzene and trichloroethylene. Notable exposure reduction by wearing face masks was confirmed by a consumer panel of ten people carrying out routine bathroom clean-up. This result suggests that face masks may be a universal and cost-effective tool to reduce respiratory exposure to reactive harmful chemicals.