COLUMBUS (WCMH) – An infectious disease expert from Ohio State University said aerosol particles expelled by someone with a virus can travel further than six feet.
Environmental Engineer with Ohio State University Public Health Dr. Mark Weir joined Ohio Gov. Mike DeWine during the state’s coronavirus update Tuesday.
“Aerosols in general at first sound kind of scary, especially when somebody’s talking about airborne,” Weir said. “When somebody says the word, ‘airborne,’ people start to react to that.”
Speaking, coughing, and sneezing release different amounts of droplets into the air. Those droplets tend to fall somewhere between three and six feet because of their size – which Weir said was about 3 to 4 microns. However, the smaller particles – the aerosols – tend to travel further.
“It all depends on the shape of your mouth when you’re talking, how forcefully you’re talking, how quietly you’re talking, how much you’re coughing, the type of coughing that you’re doing, things like that,” Weir said. “There’s a lot that goes into it.”
The majority of what people expel are droplets, but there are aerosols as well.
He added that not all aerosols contain viruses.
Based on data presented by Weir, aerosols can hang in the air for as long as 15 minutes and travel up to 10 feet, depending on the spacing of the room, ventilation, and other factors.
The aerosols can mix in the environment, but doesn’t end up contaminating the entire room, he added.
“How the air flows through the room dictates where it’s going to be able to deposit on surfaces, who’s going to be able to inhale it later on, and where it’s going to go into the ventilation system,” Weir said.
Weir also said strong indoor ventilation, hand washing, face masks, and social distancing help fight the spread of any virus.
“Between the virus and you, there are certain walls you can put in place,” he said.
Weir cautioned that ventilation is not the same as air conditioning or heating, saying ventilation is the circulation of air within a building, and the more the air moves, the better the air quality will be. He said there are three components to good ventilation: air exchange rates, make up air (air brought in from the outside), and filtration.
In order to become infected with COVID-19, the virus has to reach the back of a person’s throat, Weir said. It then begins to infect the cells that make up that part of a person’s respiratory system.
“What we’re talking about is if the majority of them that come out are droplets, that means that a smaller amount are going to be aerosols and it still takes a fairly good amount of virus for you to be able to inhale and actually become sick,” he said, adding that a lot of the current research is looking into just how much aerosol it takes to make someone sick.
“We’ve known for a little while that aerosols are a component, but how important those aerosols are is the question,” Weir said.