Many people have taken to valve masks because they are more breathable, allowing air to pass through the vent. However, the very thing that makes them appealing is also what makes them harmful. According to The Arizona Republic, Kai Singbartl, MD, the chair for infection prevention and control at the Mayo Clinic, said these masks “defeat the purpose” because “they are unfiltered.” The air that escapes through the vent could also carry viral droplets, which puts others at risk.ae0fcc31ae342fd3a1346ebb1f342fcb Kristine Romin, MD, told the newspaper, “In a sterile field, they’re absolutely banned because it allows unfiltered, exhaled air in.” Romin is a doctor at Camelback Dermatology & Skin Surgery, another place where valve masks are banned in Arizona. Not only does Mayo Clinic forbid people from wearing valve masks in their hospital—a whole county has also banned them. Maricopa County’s mask mandate explicitly says valve masks do not comply with their requirements. Per The Arizona Republic, the mask mandates in Yuma, Pima, and Santa Cruz counties have similar stipulations. While the valve mask may keep the wearer safe, it puts others at risk. Rajiv Garg, MD, Directorate General of Health Services in India, wrote a letter to emphasize that using valved respirator masks “is detrimental to the measures adopted for preventing the spread of coronavirus as it does not prevent the virus from escaping out of the mask.” RELATED: For more up-to-date information, sign up for our daily newsletter. Nikhil Modi, MD, explained to The Indian Express that “when you exhale, the expired air goes out of the valve in the N-95 mask. If the person wearing such a mask is infected, the COVID-19 virus can spread through the exhaled air into the atmosphere, which increases the risk of contamination of other people. So, in a way, it fails the coronavirus-control strategies.” Mask mandates will continue evolving as experts’ understanding of the virus and various face coverings evolve. In the meantime, one thing we know for certain is that wearing a mask with a valve is just about as useful to those around you as not wearing a mask at all. And for more masks to avoid, This Is the Face Mask the CDC Doesn’t Want You to Wear.