The mayor made the announcement Thursday afternoon, but was quick to clarify this does not mean a professional or surgical mask -- those should be left for first responders and healthcare workers.
The face coverings can be "homemade" and can consist of a bandana, a scar or another piece of clothing.
Scientists say they've been looking at data from other countries where everyone wears masks. They have concluded the most important thing isn't to use it for protection from others, but instead to protect others from you.
But officials stress wearing a mask is just in addition to everything else that should be done to fight the coronavirus.
"Remember your eyes are not in the mask, so if you're touching things and then touching your eyes ,you're exposing yourself in the same way," said Dr. Deborah Birx. "So we don't want people to feel like 'oh I'm wearing a mask, I'm protected and I'm protecting others.' You may be protecting others, but don't get a false sense of security that mask is protecting you from getting infected."
De Blasio's guidance is just that -- an advisory -- and it is not expected to be enforced for the foreseeable future.
The mayor says there are more important things to achieve with enforcement such as sheltering in place and social distancing.
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