BOSTON (WBZ NewsRadio) — A health expert in Massachusetts is questioning whether it's time to take the masks off when we go outside.

According to Dr. Paul Sax, the Clinical Director of Infectious Diseases at Brigham and Women's Hospital, public policy on masking requirements should be based on our best understanding of the science of Covid-19.

In a blog post to the New England Journal of Medicine, Dr. Sax writes that doing things like walking, hiking or jogging outdoors does not typically spread Covid-19 -- and the real danger comes in crowded, indoor spaces with poor ventilation.

"Even if I, as a fully vaccinated person, were asymptomatically carrying SARS-CoV-2 — already exceedingly unlikely on any given day — the virus would be rapidly diluted by the extraordinary ventilation conferred by just being outside," Dr. Sax said in the post.

The debate comes as the state of New Hampshire lifted it's mask mandate last Friday.

Dr. Sax said that masks should definitely still be worn in public or crowded areas where you can't stay six feet apart or if you are indoors -- but the state should consider easing the restrictions for those lower transmission settings outside.

The current guidelines in Massachusetts require wearing a face covering in all public places, whether indoors or outdoors - even when it’s possible to maintain social distancing from others.

Massachusetts Gov. Charlie Baker has indicated that he has no plans to change the mandate, and has said his decisions are based off federal guidelines and the number of people vaccinated in the state.

WBZ NewsRadio's James Rojas (@JamesRojasWBZ) reports.