Huo Jingnan | KUNC

Huo Jingnan

More widespread wearing of face masks could prevent tens of thousands of deaths by COVID-19, epidemiologists and mathematicians project.

A model from the University of Washington's Institute for Health Metrics and Evaluation shows that near-universal wearing of cloth or homemade masks could prevent between 17,742 and 28,030 deaths across the US before Oct. 1.

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With traffic dramatically down in recent months, the United States is in the middle of an accidental experiment showing what happens to air pollution when millions of people stop driving.

Updated at 10:10 p.m. ET

One month ago today, President Trump declared a national emergency.

In a Rose Garden address, flanked by leaders from giant retailers and medical testing companies, he promised a mobilization of public and private resources to attack the coronavirus.

"We've been working very hard on this. We've made tremendous progress," Trump said. "When you compare what we've done to other areas of the world, it's pretty incredible."

But few of the promises made that day have come to pass.

On Weibo, the Chinese version of Twitter, user 一只猫叫鱼Yu kept a public diary of her lockdown experience in Wuhan, China. On day 29, she described losing track of time. "I watch the days go by one after another," she wrote. "I don't know how long days like this are going to last."