“If I’m hanging that in my rearview mirror and then I have the air conditioner blasting, is what’s on that mask now blowing around inside my car?” Jade Flinn, RN, a nurse educator for the Biocontainment Unit at Johns Hopkins Medicine, said in a recent interview with The Washington Post. This reasoning is exactly why medical experts have cautioned against using air conditioning in enclosed spaces, like restaurants or cars. The safest thing to do in a car right now is to keep your mask on and roll down the windows, especially if there are other passengers in the vehicle who you don’t live with. According to the Centers for Disease Control and Prevention (CDC), you should “avoid using the recirculated air option for the car’s ventilation” and instead, “use the car’s vents to bring in fresh outside air and/or lower the vehicle windows.“ae0fcc31ae342fd3a1346ebb1f342fcb “When the windows are closed, SARS-CoV-2 (in fine aerosol particles that cause COVID-19) accumulates in the car cabin,” Harvard T.H. Chan School of Public Health’s Joseph Allen and Jack Spegler and Portland State University’s Richard Corsi wrote for USA Today. “With each new cough, the concentration builds up with no significant dilution happening. But even cracking one window open just three inches can keep this at bay.” And for those hailing a cab or getting in a Lyft or Uber during the pandemic, the CDC says to make sure to sit in the back seat, too. RELATED: For more up-to-date information, sign up for our daily newsletter. If you do decide to remove your mask in the car—like when you’re running a quick errand by yourself—it’s important to store it in a place where it won’t get contaminated, such as a clean paper bag, Michael Knight, MD, an assistant professor of medicine at George Washington University, told The Washington Post. Or, if that’s not an option, “remove the mask from the ear loops… and fold it, keeping the inner parts touching each other” and set it on the seat beside you, Knight explained. And for more expert COVID advice to keep you safe, check out 50 Essential COVID Safety Tips the CDC Wants You to Know.