Ventilation is one component of maintaining healthy environments, and is an important COVID-19 prevention strategy for schools and childcare programs. Wearing a well-fitting, multi-layer mask helps prevent virus particles from entering the air or being breathed in by the person wearing a mask. Good ventilation is another step that can reduce the number of virus particles in the air. Along with other preventive actions, ventilation can reduce the likelihood of spreading disease. Below are ways you can improve ventilation in your school or childcare program, whether in a large building or in a home.