They appeared in this week's vice Presidential debate, are used to separate restaurant tables and are in virtually every retail store as you check out. Plexiglass shields have become the silent, see-through hero in the age of coronavirus. Researchers have determined that the coronavirus travels mostly through droplets and aerosols, released when people speak, exhale, cough, or sneeze. Most are heavy and will drop to the ground within six feet. However the smaller droplets will float in the air and can be carried in air over long distances. Plexiglass shields were erected to prevent those lighter particles from moving from one person to the next. But what we are finding out is they do very little and offer a false sense of especially in smaller room or in large rooms with a lot of people. The barriers can actually reduce the HVAC ventilation effectiveness in replacing indoor air with outdoor. Plexiglass does have its benefits, primarily in blocking the spread of droplets in cases where people cannot stay six feet apart, such as at a checkout counter. It works just like you’d expect—droplets from a person’s nose or mouth would hit the plexiglass before they can hit, say, your face. Plexiglass doesn’t eliminate the need for wearing masks and maintaining airflow and filtration systems but, rather, works best in combination with these other precautions. As we are finding out, masks, filtered air, washing hands and Plexiglass doesn’t eliminate the need for wearing masks and maintaining airflow and plexiglass barriers all work in tandem to reduce the spread of COVID-19.