Daily harmful noise exposure affecting thousands, study shows

An ongoing study on noise levels has found that up to a quarter of participants were getting potentially harmful noise exposures on a daily basis.

Dr Rick Neitzel, who is an exposure scientist at the University of Michigan, is involved in the Michigan Public Health Apple Hearing Study.

The partnership between the University of Michigan and Apple is undertaking research which involves up to 180,000 people regularly reporting on the noise around them.

Neitzel told Sunday Morning that one of the features of humans becoming increasingly urbanised was that people were now encountering noise almost every hour of every day.

People were given the chance to voluntarily participate in the research and could share information such as how long and loud they were listening to music and other media through their headphones, he said.

They could also share noise from the ambient environment that could be measured by an Apple watch, as well as the results of hearing tests that can be taken on Iphones they're using, he said.

Analyses and study were ongoing but "found pretty consistently that somewhere between say 18 and 25 percent of people seen to be getting potentially harmful exposures on a daily basis, either from their ambient environment or from their music", Neitzel said.

It was okay to have a relatively short period of high sound so long as the rest of the day was relatively quiet, he said.

It was also acceptable to have much longer exposures to sound at lower volumes, he said.

"One of the things we're trying to do in our study is to identify well what characteristics, what factors about a person, might make them more likely to be in that category of high level plus high duration."

How loud people have things on their headphones was partly behaviour based, but could also result from equipment differences, he said.

"So two people sitting side by side on the same bus or the same tube train in London ... may be choosing to listen to their headphones at a different volume.

"They might have different headphones that they're listening through, one might have for instance active noise control, that's kind of eliminating some of that background sound and letting them listen at a quieter and a safer volume compared to the other person."

Where a person lived could also affect the level of noise they were exposed to, he said.

Living in a rural area did not necessarily mean people were exposed to less damaging sounds, he said.

"One of the things that we're seeing in this study is that people in the countryside can have exposures that are every bit as loud, they're just coming from different activities for instance a noisy job instead of a noisy commute."

The study also found that participants in the US who were Black or Hispanic tended to have higher noise exposures than those from other ethnic origins, he said.

"That may be partly due to where they live, the types of jobs that are available to them - we're still unpacking that."

Advice says that your ears should not receive noise above 70 decibels over a 24 hour period.

Neitzel said that was not exceptionally loud and would be at the level of a dishwasher or a quiet vacuum cleaner.

"Seventy decibels as a 24 hour average is considered the level which if you stay below that you have zero risk of hearing loss from noise and the higher you get above that the worse the risk of hearing loss becomes."

Hearing loss was insidious, he said.

Even working in a very loud job it could take five to 10 years for hearing loss to impact you, he said.

At the point where you realised you could not hear a conversation or the television the hearing loss would have already set in and be irreversible, he said.

How to protect your hearing

Neitzel said phone manufacturers provide users with the ability to set volume levels in order to protect their hearing.

A number of apps that could be downloaded on smartphones which would give a noise reading of how many decibels there were in the environment, he said.

There was a difference between noise cancelling and noise blocking headphones, he said.

"Noise cancelling is generally considered to be electronic circuitry in your headphones or your earbuds that essentially cancel out the noise that's coming into your ears, where as noise blocking is simply a headphone or earbud that's designed to physically block that noise and prevent it from getting in.

"Both of those can be incredibly effective at cutting out outside noise and letting you focus on the noise, the sound that you're trying to focus on from your media."

Vulnerable road users such as cyclists or joggers should not completely block their ears to listen to sound given that "the ears were one of the best early warning systems" for impending danger, he said.

"So bone conduction headphones and a lot of more modern earbuds that have active noise cancellation now have essentially transparency modes where they'll let some of that sound in so you're not completely isolated from your environment."

Those two options were preferable "to just blocking up your ears and hoping for the best," he said.

Ultimately a good approach was to try to improve urban design to ensure environments were quieter and could ensure good quality of life without excessive noise exposure, he said.

Neitzel does not like open plan office spaces as their noise levels can act as a terrible distraction.

"I've worked in one and it was the worst working environment I've ever worked in and a lot of that is due to the sound that just passes openly through the whole environment."

People would not accept things like contaminated water, air pollution or pesticides in their food, but they do not think twice about noise, he said.

"Part of the reason is that we haven't done a very good job in educating the public that noise is a pollutant just like all those other things and noise is really bad for us, just like all those other things."

Those in the hearing loss prevention and noise communities needed to lobby for governmental change on noise which would make everyone healthier and happier, he said.