Frank Helleis had an idea. His wife was a teacher at a local elementary school in their hometown Mainz, Germany. It was early in the pandemic and educators around the the world were trying to figure out how to balance the need for education and the need for safety in public health. Helleis is a professor of engineering at the Max Planck Institute for chemistry who studies aerosols, or how droplets of stuff travel in the air. His idea was to set up a unique set of fan structures above each desk in classrooms, guaranteeing a fresh airflow and reducing the threat of covid transmission. They found their setup could remove 90% of artificially generated aerosol particles in their experiments at the school. The setup was extremely low-cost and could be built by teachers and students themselves.