How Far Will A Cough or Sneeze Travel?
COVID-19 is still spreading and health officials are recommending people to social distance and stand 6 feet apart. Unfortunately, germs expelled from sneezing or coughing travel farther than 6 feet.
A study conducted at the Massachusetts Institute of Technology concluded that germs from one sneeze could travel from 19 up to 27 feet at 100 miles per hour, which is significantly farther than the recommended social distance of 6 feet. Environmental conditions play a key role in the distance a sneeze will travel. If the air is warm or moist, droplets will travel farther for a longer amount of time.
Researchers in Finland created a video showing how far particles can travel in a grocery store and concluded that the particles may remain in the air for several minutes. According to Dr. Sandhu, "Someone may have coughed or sneezed in that vicinity five or 10 minutes before you got there or maybe in the aisle over and now with the ventilation system, is carrying that to your aisle or other aisles." Sandhu also said that aerosol particles remain in the air for a longer period and studies suggest COVID-19 is a droplet infection.
A research lab at Florida Atlantic University conducted an experiment to measure the power of a cough. They filled a dummy’s mouth with a combination of glycerin and water and then with a pump, forced the dummy to cough to measure the distance the droplets travel.
"It generates particles on the order of 10 to 20 microns, which is roughly close to what the smallest droplet sizes are when we cough,"
- Sid Verma, Assistant Professor of
Engineering at Florida Atlantic University
Immediately, the droplets traveled three feet. Within five seconds, the droplets were at six feet and then nine feet in about 10 seconds, which is beyond the recommended social distancing guidelines. The droplets continued moving forward for another 30 to 40 seconds to travel an additional three feet. The simulated droplets repeatedly traveled past 6 feet, often doubling in distance
"At nine feet, they could linger for, provided it’s still air, two to three minutes, but the concentration is less than what it would be at six feet..."
- Manhar Dhanak, Chairman of the Engineering
Department at Florida Atlantic University
The droplets become less dense the further they travel in the air, still with the ability to carry disease. During the experiment at Florida Atlantic University, they put a mask on the dummy. The particles from the dummy dispersed from the sides of the mask and still traveled a short distance. Droplets from a cough can linger in the air up to three minutes. "Six feet is the minimum distance that you should keep. It seems that...further is better," Dhanak said.
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