That's the recommendation further down in the article:

> Both Giesbrecht and Kennedy say a simple face covering, such as a fabric mask, neck warmer or scarf, can go a long way to protecting the lungs from being irritated.

> "If you cover your mouth, you're essentially warming the air and humidifying the air in a very productive manner," said Kennedy. "So essentially, your lung has to deal with less cold, dry air."