Modern jet air hand dryers have the same impact on our ears as a close-range pneumatic drill, according to a hearing aid company.

Jonathan Ratcliffe from Audiologist.co.uk claims that powerful drying machines can cause lasting damage to children, the elderly and those with hearing problems.

“The effects are particularly dangerous for children as the machines are typically positioned at the same height as their head which means they are getting it full blast,” he says.

According to Ratcliffe it is generally accepted that 85dB is the maximum sound level that we can safely be exposed to continuously. However, he adds that powerful air dryers and pneumatic drills produce noise levels of 90dB and more.

'You're standing for up to a minute in front of a machine that is making as much noise as a construction worker drilling a hole in the road,” says Ratcliffe. “The only difference between him and you is that he's been issued with ear defenders."

Researchers from Goldsmiths University of London in 2013 carried out an acoustic test and found the sound decibels reached by high-speed dryers was 11 times higher in a typical public toilet than in a laboratory.

According to study author Dr John Levack Drever such high noise levels can cause discomfort to elderly dementia sufferers; affect the navigation of visually-impaired people and force hearing aid users to turn off their devices in public toilets.

“Manufacturers tend to test hand dryers in ultra-absorbent acoustic laboratories which is perhaps why actual sound levels are so much higher than those advertised,” he said.

Since toilets are enclosed spaces with tiled, stainless steel and mirrored surfaces, any sound is likely to be amplified which increases the pressure on the eardrums, claim experts.