Wherever people congregate, good air quality is important to reduce disease transmission and maintain a healthy workplace. When workers are living in close quarters, or working indoors together, using air filter is a good way to reduce germs and contaminants in the air. Below are pdfs with descriptions on how to build your own air filters.
The four-filter Corsi-Rosenthal box is an effective air cleaner. Making one is pretty easy. It involves taping a fan and four filters together, with cardboard on the bottom and top. When there’s no space for a four-filter box, a one-filter version is useful. It’s less expensive to make, although the filter needs to be changed more often.