evidence: On the Flip Side of Mask Wearing: Increased Exposure to Volatile Organic Compounds and a Risk-Reducing Solution - PMID: 34596392 - DOI: 10.1021/acs.est.1c04591 On the Flip Side of Mask Wearing: Increased Exposure to Volatile Organic Compounds and a Risk-Reducing Solution Surgical masks have been worn by the public worldwide during the COVID-19 pandemic, yet hazardous chemicals in the petroleum-derived polymer layer of masks are currently ignored and unregulated. These organic compounds pose potential health risks to the mask wearer through dermal contact or inhalation. Here, we show that surgical masks from around the world are loaded with semivolatile and volatile organic compounds (VOCs), including alkanes, polycyclic aromatic hydrocarbons (PAHs), phthalate esters, and reactive carbonyls at ng to μg/mask levels. Naphthalene was the most abundant mask-borne PAH, accounting for over 80% of total PAH levels; acrolein, a mutagenic carbonyl, was detected in most of the mask samples, and di(2-ethylhexyl) phthalate, an androgen antagonist, was detected in one-third of the samples. Furthermore, there is large mask-to-mask variability of the residue VOCs, revealing the uneven quality of masks. We confirm that masks containing more residue VOCs lead to significantly higher exposure levels and associated disease risks to the wearer, which should warrant the attention of the general public and regulatory agencies.