How to Make Homemade Face Masks More Effective—and How to Wear Them Right

Five months after coronavirus took root in the U.S., face masks remain one of the most controversial and confusing parts of the pandemic.

Changing public-health messaging hasn’t helped. In March, when personal protective equipment (PPE) was running short, top U.S. public-health officials told Americans that the general public did not need masks because they don’t fully block respiratory particles that spread COVID-19, such as those in a sick person’s cough or sneeze. Most masks are best at preventing particles from getting into the air where others might inhale them, so,...