Coronavirus

As students head back to school, parents and teachers are increasingly concerned about how the coronavirus could spread — especially in buildings with inadequate ventilation. 

John Lednicky studies viruses at the University of Florida. "There was a lot of controversy about SARS-CoV-2 being transmitted or not being transmitted through airborne routes," Lednicky told CBS News.

Analyzing air samples in a hospital room, Lednicky's team found infectious virus can spread through the air — up to 16 feet away from an infected patient — through tiny droplets called aerosols.

"Oh, this is the smoking gun everyone has been asking for!" said Linsey Marr, a civil and environmental engineering professor at Virginia Tech who studies how viruses travel through the air. 

"We're talking about a virus that is present in very small droplets, tiny ones that we call aerosols that can travel much farther through the air and remain in the air for minutes to hours at a time," Marr explained.

That's important because, until recently, attention has mainly focused on respiratory spread of the virus within 6 feet.

Aerosols can be produced just by talking. A classroom simulation shows how the spread of the virus is significantly cut down simply by placing ventilation near a teacher.

"Once we acknowledge that virus is transmitting through aerosols, we can then take steps to address that and to reduce that risk," said Marr.