你的口罩严不严实？有效吗？怎样自造无边缝口罩？
Does your surgical mask or DIY face mask have gaps on the sides? Ignoring
this question is unsafe and you risk your own health. This is increasingly
important when the experts are changing their strategies and asking healthy
people to wear masks.
For more details, check out: http://geniusasian.com/custom-tightly-diy-mask-filter-replace/ https://youtu.be/79cleCN1oiY
