Aerosol impaction

"Okay kiddo, you know how when you sneeze or cough, some of the stuff that comes out of your mouth can float in the air? Well, big people have a special way of catching some of that stuff before it can make us sick. They use something called an aerosol impaction. It's like a big air filter that catches all of the little things floating in the air that might make us sick. When air flows through the filter, the little things stick to it so they can't go any further. Then, the clean air comes out the other side. It's kind of like catching bugs in a bug net!"