An overlooked source of inhalational and dermal exposure to bisphenol A and its chlorinated derivatives in disposable face masks.

The presence of emerging and toxic chlorinated bisphenol A derivatives (ClxBPA) in disposable face masks (DFMs) remains unconfirmed. A total of 123 DFMs of various types, sourced primarily from China with additional samples from other Asian regions, North America, and Europe were analyzed. The results illustrated bisphenol A (BPA) was detected in all samples, while 3-monochloro bisphenol A (MCBPA) and 3,3',5,5'-tetrachloro-bisphenol A (TCBPA) were found in over 65% of DFMs. BPA exhibited the highest concentrations (geometric mean: 11.6 ng g-1), followed by TCBPA (0.0446 ng g-1), MCBPA (0.0234 ng g-1), 3,3'-dichlorobisphenol A (DCBPA-1, 0.0179 ng g⁻¹), 3,3',5-trichloro-bisphenol A (TriCBPA, 0.0169 ng g-1), and 3,5-dichloro bisphenol A (DCBPA-2, 0.0142 ng g-1). Notably, the proportion of DFM samples in which at least one ClxBPA congener was detected reached 92.7%, indicating the widespread occurrence of ClxBPA in DFMs. The concentration levels of BPA and ClxBPA varied by mask material but not between adult and toddler masks or across production regions. Exposure assessment indicated that occupational users and toddlers face higher BPA and ClxBPA exposure risks, particularly when using N95 and disposable activated carbon masks. Given the reported toxicological effects of ClxBPA, the health risks posed by these emerging contaminants deserve further attention.