Researchers at UCLA find face coverings are really effective at reducing the spread of COVID-19.
They tested everything from cloth to surgical masks, with and without a face shield, to see how much they can reduce airborne particles when someone coughs indoors.
And they found even just a cloth mask works pretty well.
"It was a surprise to us when we start experiments, we expect a relatively low-efficiency,” says Yifang Zhu, a professor in UCLA's Department of Environmental Health Sciences.
“Even a single cloth mask can reduce cough particles by 77 percent, that is rather to someone not wearing a mask at all," she says.
She says surgical masks were even more effective.
“People should wear their masks. Just go ahead and wear your mask. It’s the simplest thing people can do to help with this pandemic,” she says.
The study also found that with no face covering, cough particles can easily travel more than six feet.
California surpassed a grim milestone this week: 1 million confirmed coronavirus cases.