evidence: COLLEGE PARK, Md. – In a head-to-head comparison of masks worn by people with active COVID-19, the inexpensive "duckbill" N95 came out on top, stopping 98% of COVID-19 particles in the breath of infected people from escaping into the air. Led by researchers from the University of Maryland School of Public Health (SPH), results showed other masks also performed well, blocking at least 70% of viral particles from escaping from the source – an infected person’s exhaled breath. [...] "The research shows that any mask is much better than no mask, and an N95 is significantly better than the other options. That’s the number one message," says the study’s senior author, Dr. Donald Milton. Milton is a UMD SPH professor of environmental health and a global expert on how viruses spread through the air. [...] "Data from our study suggests that a mildly symptomatic person with COVID-19 who is not wearing a mask exhales a little over two infectious doses per hour," says first author Dr. Jianyu Lai, a postdoctoral researcher at the PHAB Lab. "But when wearing an N95 mask, the risk goes down exponentially."