The most important design object of our time was more than a century in the making.

Doctors started wearing the first surgical masks in 1897. They weren’t much more than a glorified handkerchief tied around one’s face, and they weren’t designed to filter airborne disease—that’s still not the point of surgical masks today. They were (and are) used to prevent doctors from coughing or sneezing droplets onto wounds during surgery.

This distinction between a mask and a respirator is important. It’s why healthcare professionals are upset that they’re being instructed to wear surgical masks when respirators are unavailable. Masks are not only made of different materials; they fit loosely on the face, so that particles can come in from the side. Respirators create an airtight seal so they...

The most important design object of our time was more than a century in the making.

Doctors started wearing the first surgical masks in 1897. They weren’t much more than a glorified handkerchief tied around one’s face, and they weren’t designed to filter airborne disease—that’s still not the point of surgical masks today. They were (and are) used to prevent doctors from coughing or sneezing droplets onto wounds during surgery.

This distinction between a mask and a respirator is important. It’s why healthcare professionals are upset that they’re being instructed to wear surgical masks when respirators are unavailable. Masks are not only made of different materials; they fit loosely on the face, so that particles can come in from the side. Respirators create an airtight seal so they actually filter inhalation...