How far do germs travel when we cough?
Cover your mouth! Coughing launches thousands of saliva droplets at up to 160km per hour.
Asked by: Misty, India
Powered by the diaphragm, abdominal and rib muscles, coughing is highly effective at clearing irritants or mucus from the lungs. Each cough expels thousands of saliva droplets at up to 160km/h (100mph). Each droplet is potentially laden with viruses or bacteria and can travel up to two metres, depending on size.
Researchers at the Massachusetts Institute of Technology, US, have discovered that an invisible gas cloud helps cough droplets to spread around a room. Smaller droplets in the gas cloud are swept around by eddies, travelling further and taking longer to settle.
Coughed droplets can enter the nose or mouth of innocent bystanders. Meanwhile, germs in settled droplets can live on some surfaces for hours, ready to transfer to an unsuspecting victim.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.
Sponsored Deals
Subscription offers you will love!
- Spread the cost and pay just £3.50 per issue when you subscribe to BBC Science Focus Magazine.
- Alternatively, lock in for longer and pay just £37.99 per year, saving 51%!
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.
