Sneezed germs travel four metres and lasts for 45 minutes in the air, study finds

Sneezed germs travel four metres and lasts for 45 minutes in the air, study finds

The spread of airborne diseases could be reduced through redesigned ventilation of offices, schools and hospitals, Queensland researchers hope.

Scientists from the Queensland University of Technology and the University of Queensland have discovered that some bacteria can spread up to four metres and remain alive in the air for up to 45 minutes after being coughed or sneezed.

The outbreak of the SARS epidemic in 2003 sparked the research of Professor Lidia Morawska, director of the International Laboratory for Air Quality and Health at QUT.

The SARS outbreak in 2003 saw about 300 people infected by one person who stayed in a Hong Kong hotel for just one night. 

Following the outbreak, questions were asked how the epidemic spread so quickly to so many people.

“Most research in this area to date has focused on laboratory-generated bio-aerosols, or airborne droplets, which are different from natural respiratory droplets generated by humans,” said Professor Morawska, who looked into the physics of infectious airborne bacteria expelled by the body.

An experiment was conducted in which two people sat in a four-metre long tunnel and the bacteria the infected subjects expelled by either sneezing or coughing was monitored and measured.

The findings, that the germs could be propelled up to four metres and infectious quantities of bacteria stayed alive for up to 45 minutes, disproved the theory from medical experts that one metre was a safe distance from an infected person.

Professor Morawska said the next stage of the research would be to test the distance and durability of different kinds of bacteria, such as those behind the common cold or flu.

She also hoped to investigate preventative measures including the effectiveness of masks and how ventilation systems help to spread the bacteria. 

“We will test masks using the tunnel again, but testing ventilation systems will be difficult because every building design is different,” Professor Morawska said.

“We have been struggling for resources because we are working in prevention, curing studies often attract more attention for grants.

“But we will look across a range of different designs because it could prevent the spread of airborne bacteria in office buildings, schools and hospitals.”

With Amy Mitchell-Whittington

Want more stories like this? Follow our Facebook feed.