Tag Archives: noise pollution

Credit: Pixabay.

How to fight noise pollution (and why your headphones might be making you deaf)

Credit: Pixabay.

Credit: Pixabay.

Our environment is such that it has become difficult to escape unnatural noise. Even electrical appliances at home put out a constant hum or beeping sound. According to a 2014 study, tens of millions of Americans suffer from a range of adverse health outcomes due to noise exposure, including heart disease, hearing loss, and even dementia. Noise pollution also has important consequences for wildlife. Bats and owls, for instance, are particularly sensitive to noise pollution. These animals rely on their keen sense of hearing — which can be 20 decibels more sensitive than our own — to hunt low humming insects and rodents. If disrupted by background noise, they’d be unable to hunt, feed, and survive.

By definition, noise pollution takes place when there is either an excessive amount of noise or an unpleasant sound that causes a temporary disruption in the natural balance. This definition is usually applicable to sounds or noises that are unnatural in either their volume or their production.

The World Health Organization calls noise pollution “an underestimated threat” that can cause “sleep disturbance, cardiovascular effects, poorer work and school performance, hearing impairment.” The agency recommends less than 30 A-weighted decibels (background noise of a quiet rural area) in the bedroom for a good night’s sleep.

In order to escape the infernal racket of urban life, many choose to go about their day wearing headphones. However, this may end up hurting our hearing more than the noise itself in the long run because so many people use the headphone at high volume to compensate for the background acoustic interference. People also wear headphones for longer periods of time now than ever before. The World Health Organization estimated that by 2050 some 900 million people around the world will have disabling hearing loss — 93 percent more than those who do today — in part because of damaging levels of sound from personal audio devices.

According to a 2018 study in Denmark, 14% of more than 3,000 9-to-11-year-old had signs of hearing loss. The main culprit was found to be damage incurred by overexposure to personal music players.

So, on one hand, people blast loud music in their headphones to cancel noise pollution, but on the hand, they’re incurring more hearing damage than they would from noise pollution alone.

How noise-canceling technology works.

How noise-canceling technology works.

An elegant solution might be using noise blocking headphones and other similar technology. To cancel noise, these headphones emit an anti-noise signal to contrast the external sounds.

“Noise-canceling headphones can minimize problems because you don’t have to play the headphones as loud to drown out noises,” says Maria Rerecich, director of electronics testing at Consumer Reports. “You can hear the music at a moderate level without having to blast it.”

Noise canceling headphones are especially recommended in very noisy environments which require you to raise your voice in order for someone to understand you. In the future, noise canceling technologies might even be embedded inside offices and homes. For instance, researchers at the University of Illinois’ Coordinated Science Laboratory have combined wireless Internet of Things (IoT) networks with noise cancellation. A microphone is placed in the environment that sense sounds and sends them over wireless signals to an earpiece. Since wireless signals travel a million times faster than sound, the earphone can receive the sound information much faster than the actual sound itself.

“This is similar to lightning and thunder — the lightning arrives much before the thunder, allowing people to prepare for the loud rumble,” said Shen’s advisor, Romit Roy Choudhury, an ECE Professor. “Similarly, our ear device gets the sound information in advance, and has much more time to produce a better anti-noise signal.”

However, that being said, people should still be mindful of how loud and how long they listen to music on their portable music players. Even if noise-canceling headphones allow you to listen to music at a more moderate level, experts still recommend people follow the 80-90 rule: that is, if you listen at 80 percent of the maximum volume, do so for no more than 90 minutes per day.

Finally, skip any type of headphones when engaging in activities that require your undivided attention and hearing, such as driving a vehicle, bicycling, or jogging in through the city. Your safety is more important than any nuisance incurred by noise pollution.

Western Bluebirds lay fewer eggs and hatch chicks with smaller bodies around noisy anthropogenic areas. Credit: Wikimedia Commons.

Oil and gas noise pollution hinders bird reproduction

Biologists found that birds which are constantly exposed to noise pollution from oil and gas operations may become chronically stressed, with grave consequences to their reproductive health. In some cases, the growth of their offspring is stunted. Scientists hope this work will help the industry design less invasive operations.

Western Bluebirds lay fewer eggs and hatch chicks with smaller bodies around noisy anthropogenic areas. Credit: Wikimedia Commons.

Western Bluebirds lay fewer eggs and hatch chicks with smaller bodies around noisy anthropogenic areas. Credit: Wikimedia Commons.

The team included scientists from the University of Colorado Boulder, California Polytechnic State University, and the Florida Museum of Natural History.

Researchers led by Nathan Kleist, who graduated with a PhD in evolutionary biology from CU Boulder in 2017, erected 240 nest boxes on 12 pairs of sites near oil&gas operations in New Mexico. The nesting habits of three species of cavity-nesting birds — the western and mountain bluebirds (Sialia mexicana and Sialia currucoides), and ash-throated flycatchers (Myiarchus cinerascens) — were followed over the course of three breeding seasons.

To assess reproductive health, researchers measured nestling body size and feather length but also took blood samples from the adult females. Across all species, the females exposed to noise pollution showed lower levels of the stress hormone corticosterone.

At a first glance, this seems to suggest that the birds are, in fact, not stressed by the noise pollution. 

“But what we are learning from both human and rodent research is that, with inescapable stressors, including post-traumatic stress disorder (PTSD) in humans, stress hormones are often chronically low,” said co-author Christopher Lowry, a stress physiologist in the department of integrative physiology at CU Boulder.

Nathan Kleist checks a bird box near an oil and gas operation in New Mexico. Credit: Nathan Kleist.

Nathan Kleist checks a bird box near an oil and gas operation in New Mexico. Credit: Nathan Kleist.

In other words, when faced with overwhelming stressors, animals will often develop “hypocorticism” as an adaptation to save energy. Hypocorticism is linked to inflammation and lower weight gain in rodents. So counterintuitively, both low and high-stress hormone levels can be unfavorable for many species since it leads to dysregulation. In this particular case, dysregulation due to noise comes with negative reproductive consequences.

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Researchers found that nestlings in the noisiest areas had smaller bodies and feathers. Females nesting in the noisiest environments also laid fewer eggs. Intriguingly enough, nestlings in lower noise also grew smaller compared to a baseline, albeit not as much as those hatched in high-noise environments. The quietest areas are exposed to more predators making the adult birds more cautious as they go to and from the nest. In loud areas, on the other hand, machinery noise masks the calls from other birds, stressing moms and nestings. The sweet spot was found to be in areas of moderate noise where nestlings seemed to grow the fastest

“If you were trying to talk to your friends and your children and you were always at a loud party, you would get worn out,” said Kleist.

What’s striking is that even the western bluebird — a species previously suspected to be resilient to noise — showed reduced hatching rates.

Though none of the three species studied by the researchers is endangered, the authors suspect that other species nesting near noisy areas — some that are endangered — experience similar effects. In 63 percent of the protected areas, anthropogenic noise already doubles background-sound levels.  

“There is starting to be more evidence that noise pollution should be included, in addition to all the other drivers of habitat degradation, when crafting plans to protect areas for wildlife,” said Kleist, now a visiting professor at State University of New York. “Our study adds weight to that argument.”

Findings appeared in the journal Proceedings of the National Academy of Sciences. 

Animals all over the world against noise pollution

A magnificent blue whale

Pollution can take numerous and unexpected shapes; one of the not-so-deadly, but still extremely unpleasant types is noise pollution. You probably don’t notice it because it’s so common, but it’s a really noisy world out there; if for a few days you were to go somewhere far away from all the fuss and noise that affect us on a daily basis, you will probably have a hard day when you come back, before you get used to all the sounds again.

The world's shipping routes. Credit: National Center for Ecological Analysis and Synthesis.

It is true that all environments have some kind of ambiental noise, caused by rivers, waves, other animals, wind, etc, but we humans have drastically increased the amounts of daily decibels out there. Basically, on land we’re dealing with cars, airports, machinery, and in the sea the problem is mostly caused by shipping, but also deep water drilling, explosions, etc. This may not seem like a big issue, but when some of the most important things in your life, like hunting and mating, are determined by sounds, you definitely have a problem on your hands.

Animals have always had ways to deal with the sounds; when it comes to short term ones, such as wind or rain; most just wait until it stops and then continue their activity. Tawny owls, for example, stop calling each other, and bushcrickets delay their nocturnal symphonies until morning when there are other noisy insects around. But anthropic noises are not short term, and humans have always been remarkably good at making noise.

Tawny Owl

The next usual approach animals take is being even louder than before. It’s something natural, everybody does it all the time (even though it’s not really a good idea, for example when your mother or daughter is screaming at you). But this comes at a cost; have you ever been to a really good concert ? If you have, the odds are you’ve come home with a really sore throat caused by screaming. This phenomenon was first described by Etienne Lombard 100 years ago, and since then, it has been used to describe the increase in amplitude of a vocalization.

Research upon Great tits, Beluga whales, orcas, manatees and numerous other species has shown that this effect can be quite common – especially as it requires quite some effort to scream all the time. This may be what causes blue whales to sing lower and lower every year, but there still is a lot we have yet to understand about the changes species undergo from loud noises.

However, one thing is loud and clear – the sounds we make have a definite impact on animals, and many of them are out there right now, screaming “Can you hear me?” louder and louder every day. Surprisingly, the answer is no.