Air-borne viruses can spread far and wide
The common cold is even more communicable than thought, as a study showed that air-borne viruses can travel long distances.Updated: May 17, 2007 15:12 IST
A new research by Queensland University of Technology has revealed that airborne viruses can spread far and wide.
Professor Lidia Morawska, director of QUT's International Laboratory for Air Quality and Health, said the study dispelled the myth that viruses emitted from humans only travel a metre in the air.
Professor Morawska and a team of QUT scientists have been studying the way droplets carrying viruses are dispersed in the air when people speak, cough, sneeze and breathe.
"The current belief is that if you are an arm's length away from someone you are protected from any viruses they might be carrying," she said.
"When we talk about infection spread we are talking about droplets emitted from humans being dispersed in the air,” she added.
As part of the study QUT designed and built a machine to measure the distance a droplet travels in the air prior to drying.
"The significant part of our research has found that rather than the droplet falling directly to the ground after leaving the mouth, the liquid component of the droplet dries in the air and the dry residue travels large distances When a droplet dries in the air the residue is carried in the air, and therefore there is a risk that people can inhale that air and become infected,” she said.
Professor Morawska said a droplet drying on a surface could be infectious but the greater danger was droplets drying in the air.
"A droplet can travel for 10 cm before it dries in the air, it doesn't immediately fall to the ground,” she said.
Professor Morawska said her research had shown that one person infected with the disease could easily spread the virus by simply breathing.
"Understanding the way viruses spread from human expiration means we can look to better design spaces, ventilation systems and filters," she said.
Professor Morawska said the next stage of the research would investigate the global effect of dried droplets in health care facilities to see how viruses were spread around the world.