Noise Pollution: Harming Nature's Balance And Health

Noise pollution is a pressing issue that affects both human health and the environment. It is caused by various human activities, from traffic and construction to industrial and military operations, and has been linked to a range of adverse effects on different ecosystems. For instance, noise pollution can disrupt the natural behaviours of animals, impair their ability to navigate, communicate, and reproduce, and even lead to their relocation or death. In marine environments, noise from shipping, seismic surveys, and military sonar activities has been found to impact whales, dolphins, and various invertebrates. On land, birds and other wildlife are affected by traffic, firecrackers, and increased air traffic. Addressing noise pollution is crucial for preserving biodiversity and maintaining the well-being of both human and animal populations.

Impact on marine life

Marine animals are extremely vulnerable to noise pollution, as they often rely on sound to survive. Visibility is often low underwater, so sound is an important sensory signal for marine wildlife, especially for whales, dolphins, and porpoises. They use sound to communicate, find prey and mates, avoid predators, navigate, and defend their territories.

Noise pollution in the ocean has increased dramatically over the last few decades, threatening the natural soundscape of the marine environment. This is largely due to human activities such as shipping, boating, oil and gas exploration, seismic surveys, explosions, construction, and the use of sonar devices. These activities can interfere with the key life functions of marine animals and even cause death.

Noise pollution can cause hearing loss in marine animals, as well as behavioural and physiological changes. It can also mask the natural sounds produced by marine wildlife, making it difficult for them to communicate and detect important environmental cues. This can affect their ability to find food, locate mates, and avoid predators. For example, studies have shown that noise pollution reduces humpback whale communication and interferes with the feeding behaviour of blue whales.

The impact of noise pollution on marine life is not limited to large animals like whales and dolphins. Even short exposure to low-frequency, low-intensity sounds can disturb the balance systems of squid, octopuses, and cuttlefish. It can also affect fish larvae, causing them to move away from their traditional habitats.

To protect marine life, it is important to reduce noise pollution in the ocean. This can be done by developing quieter technologies, implementing policies to reduce propeller noise from ships, and mitigating the sounds of sonar equipment, seismic air guns, pile driving, and construction.

Interference with animal communication

Noise pollution interferes with animal communication by masking acoustic signals that animals rely on, hindering inter- and intraspecific communication. This can cause a range of problems, from difficulty in finding food, locating mates and avoiding predators to impairing their ability to navigate, communicate, reproduce and participate in normal behaviours.

Anthropogenic noise can also cause animals to alter their natural behaviours or relocate to avoid noisy areas. Changes in animal behaviour can have flow-on effects for whole ecosystems.

Some animals change their vocal behaviour in an attempt to overcome the signal- and cue-masking effects of noisy environments. This can be done by changing the amplitude of the vocal output, shifting its frequency, or changing its temporal structure.

Animals that are particularly affected by noise pollution include birds, amphibians, reptiles, fish, mammals and invertebrates.

Changes in animal behaviour

Noise pollution has a significant impact on animal behaviour, causing changes that can have far-reaching effects on ecosystems. Animals are altering their natural behaviours or relocating to quieter areas to avoid human-made noise.

One example of this is the impact of noise on bird populations. Studies have shown that the population and diversity of certain bird species decline when exposed to continuous noise from urban environments, such as roads and cities. Some birds have adjusted their vocal calls to be heard above the noise, with male great tits changing the frequency of their calls to attract mates. However, these higher frequencies are less attractive to female great tits, placing the males in a difficult position. Urban European robins, highly territorial birds that rely on vocal communication, have also altered their behaviour by singing at night when it is quieter, rather than during the noisier daytime.

Noise pollution has also been found to affect the behaviour of scrub jays, which are common in the western United States. These birds avoid nesting in noisy areas, such as near gas wells, as the constant compressor noise drowns out their communication calls. As a result, the forests that depend on these birds for seed dispersal are declining.

In addition to birds, noise pollution impacts the behaviour of other animals, such as bats and whales. Bats, which use sound to hunt, experience decreased foraging efficiency when exposed to traffic noise. Whales, which rely on sound to communicate, navigate, and monitor their surroundings, are also affected by noise pollution. Studies have shown that humpback whales communicate less when exposed to noise, even when the source of the noise is far away.

The impact of noise pollution on animal behaviour extends beyond individual species, influencing entire ecosystems. For example, the decline of scrub jays in certain areas can lead to the disappearance of pinyon pine forests, as these birds play a critical role in seed dispersal. Similarly, the presence or absence of noise-sensitive species can reshape ecosystems by altering food webs and species combinations.

Hearing loss in humans

Noise pollution can cause hearing loss in humans, whether that's from listening to loud music through headphones, being exposed to loud drilling noises at work, heavy air or land traffic, or individual incidents where noise levels reach dangerous decibel intervals.

The World Health Organization (WHO) states that noise pollution is a state of excessive noise that "seriously harms human health and interferes with people's daily activities at school, at work, at home, and during leisure time". According to the WHO, sound levels below 70 dB are not damaging to living organisms, no matter the length of exposure. However, exposure to constant noise beyond 85 dB for more than eight hours may be hazardous.

Noise-induced hearing loss (NIHL) can be caused by a one-time exposure to an intense "impulse" sound, such as a gunshot or explosion, or by continuous exposure to loud sounds over an extended period. NIHL can be immediate or take a long time to become noticeable; it can be temporary or permanent, and it can affect one or both ears.

Sounds at or below 70 decibels (dBA) are unlikely to cause hearing loss, even after long exposure. However, long or repeated exposure to sounds at or above 85 dBA can cause hearing loss. The louder the sound, the shorter the amount of time it takes for NIHL to occur. For example, normal conversation is around 60-70 dBA, while music through headphones at maximum volume is 94-110 dBA. Fireworks produce sounds of 140-160 dBA.

Most NIHL is caused by the damage and death of hair cells in the inner ear. Unlike birds and amphibians, human hair cells do not grow back.

According to a 2011-2012 CDC study, at least 10 million US adults (6%) under the age of 70—and perhaps as many as 40 million adults (24%)—have hearing test results that suggest hearing loss in one or both ears from exposure to loud noise. Researchers have also estimated that as many as 17% of teens have hearing test results that suggest NIHL in one or both ears.

In addition to causing hearing loss, excessive noise exposure can cause irritability, anxiety, and mental fatigue, and interfere with sleep, recreation, and personal communication. Children living in areas with high levels of noise pollution may suffer from stress and other problems, such as impairments in memory and attention span.

Sleep disturbances in humans

Constant exposure to elevated sound levels, particularly during the night, can lead to measurable biological changes in the form of a stress response. This includes increased secretion of stress hormones like adrenaline and cortisol, increased heart rate, and elevated blood pressure. These physiological changes can have both immediate and long-term consequences on health. For example, poor sleep has been linked to an increased risk of cardiometabolic diseases, including hypertension, type 2 diabetes, and cardiovascular events in adults. It can also trigger endocrine and metabolic perturbations, affecting hormonal release, glucose regulation, and cardiovascular function.

In addition to the physical health impacts, sleep disturbances can result in daytime sleepiness, tiredness, annoyance, mood changes, decreased well-being, and impaired cognitive performance. These effects can influence an individual's work or school performance during the day, further contributing to the negative consequences of sleep disturbances.

Children appear to be more sensitive to noise pollution, and sleep disturbances can have detrimental effects on their development, including impaired cognition and worsening of attention-deficit hyperactivity disorder symptoms. Additionally, regular use of music players at high volumes can put children at risk of developing hearing impairments.

To mitigate the impacts of noise pollution on sleep, it is recommended to maintain a noise level of around 35 dB in the bedroom at night and 40 dB in the house during the day. Avoiding residential areas close to heavy traffic and wearing earplugs when exposed to elevated noise levels can also help prevent sleep disturbances.

Frequently asked questions