What is noise pollution?
Noise pollution, also commonly known as sound pollution and/or environmental noise is the spread of harmful levels of noise affecting both human and animal life. Noise pollution, according to National Geographic, affects millions of people globally. According to a 2005 study in the United States alone, 30 million people are subjected to hazardous noise levels daily. Noise pollution is typically generated from industrial activity, construction, freeways, and aeroplane traffic. There are, however, many other sources of noise that have dangerous decibel (dB: the measure of sound intensity) levels such as lawnmowers, jackhammers, train stations, bars/cafés and nightlife. All of which are mainstream noise pollutants to billions around the globe.
Much like light pollution, noise is not only threatening the health of billions and lessening the well-being of wildlife, but doing so with little public awareness. As David Owen claimed, “given that we evolved in a completely different sound environment, it’s astonishing that our ears – anybody’s ears – work at all.”
Conservative vs. hazardous dB:
According to the Better Health Channel established by the Victorian government, Australia, experts agree that any dB level above 85 is unsafe and causes “damage to hearing.” For clarity, 85 dB produces the equivalent amount of noise as heavy traffic. Whilst 85 dB is considered unsafe, any level of noise above 70 dB is of concern, harming both hearing (over a prolonged period of time) and increasing frustration.
The CDC (Centers for Disease Control and Prevention) claims that safe dB levels include: normal breathing (10), ticking watches (20), soft whispers (30), and typical conversations and air conditioning (60).
As for noise intensities that may increase frustration and cause hearing loss: washing machines (70) and sitting in traffic (80-85).
Activities or machines attributed to harmful noise levels include fuel lawnmowers (80-85), motorcycling (95), approaching subway trains and car horns (100), personal electronic devices set to maximum volume (105 – 110), and standing near sirens (120). Such basic and common activities as going out for drinks, listening to loud music or attending sporting events can cause hearing loss in less than 10 minutes.
The EPA (Environmental Protection Agency) and WHO (World Health Organisation) advise that environmental noise over the course of 24 hours, should remain below 70 dB to reduce the likelihood of developing noise-induced hearing loss.
What city has the worst noise pollution?
According to the UNEP (United Nations Environmental Programme) as of 2022, Dhaka – the capital city of Bangladesh – has been ranked the world’s most noise polluted city. Dhaka, with a population of 22.5 million, has recorded noise levels of between 110 dB and 130 dB in some instances. WION claims that noise levels in Dhaka are “inflicting long-term harm to local residents’ physical and emotional health.” According to WION, Dhaka had an average noise frequency of 119. In comparison, a frequency of 120 dB is the point at which noise becomes painful and dangerous to the human ear.
Following Dhaka was Moradabad in India (114 dB), Islamabad in Pakistan (105 dB), and Rajshahi also in Bangladesh (103 dB).
How does noise pollution affect animals?
Across the globe, the introduction of transportation, industrial activity and new technologies have not only created frantic and fast-paced lives for humanity but impaired breeding and sleeping cycles of wildlife. In the United States, the National Park Service found that increased noise levels affected both the comfort of animals in their once-tranquil habitat and harmed their traditional breeding cycles. A study in Idaho established a phantom road network of about 700 metres long consisting of speakers projecting the sound of a freeway through the Lucky Peak State Park. The study aimed at measuring the effects on local birds, found 31% of the birds avoided the entire area, and of those that stayed, the vast majority suffered weight loss. William Laurance, an Australian professor at James Cook University in Cairns, claimed, “I was initially surprised that even moderate road noise — comparable to a suburban setting — would have such a wide-ranging impact on migrating birds.”
The most notable influence noise pollution has, however, is on marine life. Seeing that aquatic animals rely on the use of sound to communicate, locate food, and protect themselves, the introduction of anthropogenic noise has had a profound impact.
In 2001, a Canadian team went out to study stress hormones in whale faeces by training dogs to sniff-out whale waste off the side of a boat. Comparing their stress-hormone data to an unrelated faeces study of North Atlantic right whales, the team noticed a massive drop in stress hormones over the course of just a few days. The study coincided with the September 11th terrorist attacks. After 9/11, global shipping halted temporarily and the levels of oceanic noise pollution plummeted. The Washington Post headlined: Unplanned 9/11 analysis links noise, whale stress. Science supported such claims adding, “levels of stress hormones in their feces went down, suggesting that ship noise places whales chronically under strain.”
Moreover, another study published in Science expressed concerns about deep-sea mining. The study revealed that a single extraction site could spread noise 500 kilometres (311 miles); twice the distance from Singapore to Malacca. A professor at the University of Hawaii, Craig Smith, believes his “modelling suggests that mining noise could impact areas far beyond the actual mining sites, including preservation reference zones (PRZs), which are required under draft mining regulations to be unaffected by mining.”
To list and explain all of the animals affected by noise pollution and why, could constitute chapters worth of everything-you-need-to-know environmental textbooks. From a shoal of giant squid found washed up on a Spanish beach in 2003 due to loud geophysics experiments, to velvet ant populations declining by 56% for every 10 dB increase at compressor sites. It must be stressed that so many more animals than are detailed in this text – marine or terrestrial – are significantly affected by noise pollution.
What about humans?
Resembling other forms of pollution, noise is another catalyst in the deterioration of public health. A team measuring noise pollution in the greater Paris area found places along transportation paths were most disrupted by noise, anywhere from major road networks, flightpaths, and train lines. According to both the French team and the WHO, those who live in areas with high levels of noise have a reduced life expectancy because of an increased risk of cancer, heart disease, excessive stress, high blood pressure, sleep disturbances, heart attacks, gastritis and more.
Utilising data provided from the nationwide Danish Nurse Cohort of 22,466 female nurses over the age of 44, the National Library of Medicine conducted a study to analyse the consequences of noise pollution on their health. Of the 22,466 females studied, they found that “1193 developed breast cancer in total”. Adding “[for] each 10 dB increase in 24-year mean noise levels at their residence, we found a statistically significant 10% […] increase in total breast cancer incidence.” The scientific reasoning behind why there was and is an increased risk of breast cancer development is due to the hyper-activation of the HPA axis, furthering the release of stress hormones. Excessive stress hormones have the ability to restrain anoikis – a process that destroys diseased cells and prevents them from spreading.
As for other cancers such as colorectal cancer, some studies suggest they have an association with noise pollution, however, no definitive conclusion can be made.
According to Stanford University, researchers studying 500 adults over 5 years found – even after “adjusting for other factors that contribute to cardiovascular risk”, just a 5 dB increase in the average 24-hour noise intensities boosted the chance of heart attacks, strokes and numerous other heart-related troubles by 34%. As if that wasn’t enough, the same study revealed via brain imaging, that higher levels of noise pollution “increased inflammation in the arteries” and elevated the “activity in the amygdala, the area of the brain involved in processing stress, anxiety, and fear.”
In addition to cancers and cardiovascular diseases, noise pollution has shown to lessen people’s ability to sleep and the quality of such sleep. According to the renewable energy company, Iberdrola, a reduction in sleep from noise “can have latent effects on our behaviour, causing aggressive behaviour and irritability.” Not to mention a study in Germany regarding the mental health status of those close to disruptive noise, found an increase in clinically significant anxiety and depression.
Along with the many other physical and mental implications, a study explained in the Guardian claimed that noise pollution also has detrimental impacts on student memory and academic development. Studying nearly 2,700 Spanish children in schools in Barcelona, they noticed “children exposed to about three times more traffic […] than other pupils had memory development that was 23% slower and attention ability development 5% slower over a year.”
Based on the European Environmental Agency figures, noise pollution leads to 72,000 additional hospital admissions and 16,000 premature deaths annually throughout Europe. WHO data suggests at least 1 million healthy years of life are lost yearly due to traffic-induced noise in Western Europe alone.
How can we reduce noise pollution?
Similar to light pollution, there are many simple and effective ways individuals, businesses, and governments can effectively reduce noise pollution within local neighbourhoods, green spaces, cities, transportation paths and more:
|Individuals & households||Businesses||Governments|
|Planting evergreen broadleaf trees and shrubs on your property.||Installing thorough insulation in offices or factories.||Implementing tougher noise level policies for businesses.|
|Investing in better house insulation (windows, walls, flooring).||Installing rugs or carpeting throughout office buildings.||Engaging with residents in cities to examine ways of transforming certain roads into green spaces.|
|Notifing your council/county of noise pollution nearby.||Reducing the number of loud machines running simultaneously.||Installing rubber tires or strips in subways.|
|Shutting doors separating the inside from the out when playing music, watching a movie or hosting a party.||Using centrifugal rather than propeller fans;||Developing policies that mandate prior EPA approval of exhaust systems.|
|Replacing petroleum-fueled lawnmowers or leafblowers with electric alternatives.||Discussing new business models to begin manufacturing quieter products.||Incentivising quieter means of transportation or equipment through subsidies.|
|Reducing your overseas purchases to reduce cargo shipping.||Maintaining worn or rusted equipment to reduce clutter and grinding noise.||Installing roadside noise barriers.|
|Seeking alternative food sources away from seafood.||Inserting vibration absorbers and dampers in factories.||Mandating the installation of accoustic bubble curtains when installing offshore wind turbines.|
The world is surrounded by noise. So much of the world – especially areas within urban landscapes- accept unknowingly hazardous levels of noise every day with potentially fatal consequences. As for nature, the acoustic ecologist Gordon Hempton claims that “there is not one natural place on planet earth set aside […] to noise pollution.” For our own sanity and respect to nature, something must be done to combat the pandemic of noise. Fortunately, unlike land or air pollution, once the noise is gone – it’s gone. No cleanup effort is required. If we’re not careful, however, this latest mass extinction may remove more than just life, but the very sound of silence.