Earlier on in the COVID-19 pandemic, Americans were told to wear masks in public only if they were already sick. But that advice is out the window, as experts are saying we should make our own masks to wear whenever in public. This week's Consumer Alert looks into what changed.

"It's a new virus and I think the things that people speculated on early have proven to be not so clear," says Dr. Barron Lerner, a professor at NYU Langone's School of Medicine. "The early supposition, from my understanding, was that the virus didn't last too long in the air, that it was similar to other viruses that basically come out of your mouth and go to the ground."

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New research indicates some coronavirus particles remain airborne for a few minutes, meaning they can be there beyond when a person coughs or sneezes. A mask, even one made of cloth, improves everyone's odds.

"The number I saw quoted was something like 85% of the particles probably get stuck in the mask," says Dr. Lerner. "So if you're breathing out virus, it catches 85%, and if you're breathing in virus, it prevents 85%."

Dr. Lerner advises wearing a mask while shopping or anytime you're around people, even if outdoors. You also want to wash your hands before putting the mask on and after taking it off. Avoid touching the mask on the part that covers your nose and mouth.

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Dr. Lerner suggests using your best judgment in regard to washing masks. Wash a simple cloth every day, or as often as possible if the mask won't hold up to that much cleaning.

It's been suggested that adding a fresh coffee filter between cloth layers provides added protection, but Dr. Lerner says it probably won't do anything. Though Lerner says to go ahead and do it if it makes you feel better. 

Dr. Lerner says you probably don't need a mask while getting outside exercise by yourself or while performing tasks like walking the dog.

"I see a lot of people doing that, and God bless them, that's fine. But I think if you're trying to get some exercise and keep yourself sane… you really don't need to wear a mask," Lerner says of the lower risk activities.