NBC晚间新闻 新研究揭示不同口罩防护效果（在线收听）

These days the choice of face masks can be dizzying. So researchers at Duke Health set out to find which may work best, testing 14 different types with a simple experiment designed to visualize small particles or droplets sprayed during regular speech. Researchers said the same phrase. Stay healthy, people. First with no mask, note the flashes of light. Those are the tiny particles which could contain coronavirus. If everyone wore a mask that truly blocked these particles, we would reduce the spread of a transmissible disease like covid-19. No question about it.

Medical grade N95s and surgical masks both worked well to block particles. But masks with exhalation valves won't protect those around you. Cotton masks with several layers of material did well, not a lot of droplets got through. You don't need a perfect mask to reduce community spread. But bandanas and neck gaiters didn't fare well. In fact, researchers say they may result in more small particles than no mask at all. Bottom line, Lester, researchers say masks work if they have several layers of good fabric. If you can see through it, it's probably not doing you much good.

如今，选择口罩是一件让人头疼的事。所以杜克健康中心的研究人员开始寻找最有效的口罩，他们选取了14种不同的口罩，做了一个简单的实验，使人们在日常说话中喷射出的小颗粒或液滴可视化。研究人员也是这么说的。保持健康。首先不带口罩，注意闪烁的灯光。这些是可能含有冠状病毒微小颗粒。如果每个人都戴上口罩，真正阻断这些颗粒，我们就能减少新冠肺炎这样的传染性疾病的传播。这是毫无疑问的。医用N95口罩和外科口罩都能很好地阻挡颗粒物。但是带呼气阀的口罩不能保护你周围的人。用几层材料做成的棉口罩效果很好，没有多少液滴能通过。你不需要完美的口罩才能减少社区传播。但是，大手帕和围巾的防护效果并不好。事实上，研究人员表示，它们可能会比完全不戴口罩吸收更多的小颗粒。莱斯特，研究人员表示，关键在于，口罩有好几层好的布料，才能起作用。如果你能看透它，它可能对你没有什么好处。