If you physically recoil every time someone coughs or sneezes on public transport, then we’ve got some bad news for you.
Not only are your fellow commuters really inconsiderate, but the droplets of bacteria that just shot out of the back of their throat, are going to linger in the air around you for up to 45 minutes.
And because the pathogens are airborne they are able to travel four metres in distance, so you’re not even safe at the other end of the carriage.
And you really should be covering your mouth and nose (and then washing your hands) to stop spread of infection.
The research was one of the first to study the longevity of airborne pseudomonas aeruginosa bacteria, a multi-drug resistant germ associated with hospital-acquired infections,
Professor Lidia Morawska, said: “Most research in this area to date has focussed on laboratory-generated bio-aerosols, or airborne droplets, which are different from natural respiratory droplets generated by humans in composition and mechanisms of production.”
The team were able to achieve this with a new technique that sampled two patients with cystic fibrosis and chronic pseudomonas aeruginosa infection.
They found that the bacteria decayed in two different time spans, Morawska, said: “As soon as cough droplets hit the air they rapidly dry out, cool and become light enough to stay airborne. They also partly degrade through contact with oxygen in the air, with larger droplets taking much longer to evaporate.
“We found that the concentration of active bacteria in the dried droplets showed rapid decay with a 10-second half-life for most of the bacteria but a subset of bacteria had a half-life of more than 10 minutes.”
This finding suggests that some of the bacteria are resistant to rapid biological decay and thus hang around in the air long enough to present a risk to other people, especially those with existing respiratory problems.
They speculate that differentiation between bacteria’s lifespan is dependent on where abouts they are produced in the respiratory tract.
Professor Morawska said the findings had implications for infection control in hospitals and particularly with the treatment of people with cystic fibrosis.