Does Everyone Need to Wear a Mask Outside? Experts Weigh In.

"Outside is protective, but it’s not a total risk eliminator," said Saskia Popescu, an infectious disease epidemiologist and adjunct professor at the University of Arizona Mel and Enid Zuckerman College of Public Health. "When we’re seeing transmission outdoors, it’s people who are close to each other, talking face to face. The three key factors to consider are distance, duration, and intensity," she says.