What masks work best? Dr. Melissa Perry answers viewers' questions about mask wearing

What masks work the best, cotton face coverings or medical-grade masks?
Some people even wonder if face masks work at all to prevent COVID-19.
News 12's Elizabeth Hashagen is joined by Dr. Melissa Perry to answer viewers' questions about mask wearing.
Dr. Perry is the chair of the Department of Environmental and Occupational Health at the George Washington University, Milken Institute School of Public Health. She has also served on the Board of Scientific Counselors at the CDC.