Keep masks on if public transit ventilation is poor, says ER doc

Written by Danielle Chiriguayo, produced by Brian Hardzinski and Marcelle Hutchins

The chances of catching COVID while flying are relatively low, but Dr. Mark Gendreau says there are steps you can take to prevent infection. Photo by Shutterstock.

Masks are no longer required in airports, on trains, and other forms of public transportation. The change in policy comes after a Florida federal judge struck down the mask mandate for travelers on Monday. In LA, some transit agencies are still asking riders to wear face coverings. But with the highly contagious Omicron variant still spreading in the U.S., should we be ditching our masks? 

Sitting on an airplane without a mask can be relatively safe, since in-flight ventilation systems are filtering the air every couple of minutes. But these systems are not designed to filter out infectious particles, and passengers have a 3%-11% chance of catching COVID while flying. That’s all according to Dr. Mark Gendreau, chief medical officer of Beverly and Addison Gilbert Hospital in Massachusetts. 

“The [efficacy] is better than what you would get if you were in an operating room. But as you get up and move about the cabin, [and] if everybody's got their mask off, you're going to get into other people's space, and might inhale a couple of thousand or a couple million COVID viral particles. And that will set off a high potential of you catching infection,” he explains.

Gendreau says there are four circumstances when air travelers should wear their masks: in the security line, while boarding the airplane, in the plane’s bathroom, and while deplaning. He notes that it’s especially crucial to keep your mask on while getting off the plane because many of the plane’s systems are off, including the ventilation system.

“It's very quiet in there because you're not hearing any hissing from the ventilation system because the engines are off. And it takes a few minutes for that ground crew to hook up that auxiliary power unit that enables the ventilation system to turn back on again. So you definitely want to stay at your seat, wait until it's your turn to get up, and get off the aircraft.” 

Other forms of transportation such as buses, trains, and ride-hailing services have suboptimal ventilation. If it's possible, Gendreau recommends keeping the mask and staying socially distanced from other commuters.



  • Dr. Mark Gendreau - emergency medicine doctor and chief medical officer of Beverly and Addison Gilbert Hospital in Massachusetts