Noise Pollution: Harmful Effects On Human Health

Noise pollution, or environmental noise, is any unwanted or disturbing sound that affects the health and well-being of humans and other organisms. It is a growing problem across Europe, with 20% of the population exposed to long-term noise levels that are harmful to health. The impact of noise pollution on human health is often underestimated, and it has been deemed a growing danger to the health and welfare of the Nation's population by US agencies such as the EPA. Noise pollution has been linked to various health issues, including hearing loss, tinnitus, sleep disturbances, stress, cardiovascular disease, and cognitive impairment in children. It is the second largest environmental cause of health problems, after air pollution.

Cardiovascular and metabolic health

Noise pollution has been linked to a range of cardiovascular and metabolic health issues, with research showing that it can cause or exacerbate cardiovascular disease, type 2 diabetes, sleep disturbances, and stress.

Noise pollution has been found to increase the risk of cardiovascular disease, with epidemiological studies showing a dose-dependent association between noise caused by air, road, and rail traffic, and elevated cardiovascular morbidity and mortality. Research has also shown that traffic noise at night can cause sleep disruption, elevated stress hormone levels, and increased oxidative stress, which can lead to vascular dysfunction and high blood pressure, further elevating cardiovascular risk.

The World Health Organization (WHO) has stated that, in Western Europe, noise pollution leads to:

• 61,000 cases of ischemic heart disease
• 45,000 cases of cognitive impairments in children
• 903,000 cases of sleep disturbance
• 22,000 cases of tinnitus
• 654,000 cases of noise annoyance

In the EU, it is estimated that long-term exposure to environmental noise causes 12,000 preventable deaths and contributes to 48,000 new cases of ischemic heart disease each year. Research has also shown that noise-related stress is a contributing factor in the development of noise-induced cardiovascular disease, with the risk of cardiovascular issues increasing with the extent to which an individual perceives noise as annoying.

Furthermore, a recent study found that every 5-decibel increase in the average 24-hour noise level was associated with a 34% increase in heart attacks, strokes, and other serious heart-related problems. This study also showed that higher levels of noise exposure were associated with increased activity in the amygdala, the area of the brain involved in processing stress, anxiety, and fear, as well as increased inflammation in the arteries, a known trigger for cardiovascular problems.

Mechanisms

The exact pathophysiological mechanisms by which noise causes cardiovascular issues are still being studied. However, it is believed that long-term noise leads to stress reactions or noise annoyance reactions, which activate the sympathetic nervous system and increase the excretion of stress hormones. This, in turn, can lead to the development of oxidative stress and inflammatory processes, resulting in disruption of vascular and endothelial function.

Prevention and mitigation

Given the negative impact of noise on cardiovascular and metabolic health, preventive measures are necessary to protect individuals from the harmful effects of noise. The WHO has set noise guidelines recommending much lower mean noise levels during the day and at night for aircraft, road traffic, and rail traffic.

Sleep

Noise pollution can have a significant impact on sleep quality, leading to both short-term and long-term health consequences.

Short-Term Effects

A good night's sleep is essential for feeling rested and performing well during the day. Even if noise does not wake you up, it can still affect your sleep structure and biochemistry. For example, a 2011 study found that regular exposure to sleep-interrupting noise can extend the duration of light-stage sleep while reducing the duration and quality of deeper-stage, recuperative sleep. This can lead to sleepiness, irritability, and poorer mental health the next day.

Long-Term Effects

Over time, poor sleep quality due to noise pollution can lead to more serious health issues. Environmental noise, especially from transportation, is considered a significant cause of sleep disturbances, which are associated with various negative outcomes in adults and children. These include cardiometabolic, psychiatric, and social problems.

Nocturnal environmental noise can provoke measurable biological changes in the form of a stress response, affecting sleep architecture and subjective sleep quality. It can lead to increased secretion of stress hormones like adrenaline and cortisol, increased heart rate and blood pressure, and elevated motility. These changes can have long-term consequences on health, including an increased risk of cardiovascular disease, type 2 diabetes, and certain types of cancer.

Additionally, the World Health Organization (WHO) has identified seven categories of adverse health and social effects of noise pollution, including sleep disturbances as the most deleterious non-auditory effect due to its impact on quality of life and daytime performance.

Strategies to Reduce Noise

To mitigate the impact of noise on sleep, several strategies can be employed:

• Insulating windows or sealing air gaps to block outside noise
• Turning off alerts and notifications on electronic devices
• Adding soft surfaces like rugs, cushioned furniture, or thick curtains to absorb sound
• Reducing appliance noise by repairing or replacing noisy appliances
• Using earplugs or noise-cancelling headphones to block out noise
• Negotiating with household members to reduce noise, such as requesting they use headphones or preparing meals and laying out clothes ahead of time

Stress

Noise pollution has been linked to increased stress levels in humans. The constant barrage of unwanted sounds can trigger anxiety and stress, with continued exposure intensifying these effects. People exposed to noise pollution may experience feelings of irritability, frustration, and anger. The inability to control noise levels in one's environment further exacerbates the impact on mental health.

Noise pollution affects people of all ages, but children are particularly vulnerable. Studies have found that children living near noisy areas, such as airports or busy streets, experience higher levels of stress and other problems like impairments in memory, attention, and reading skills. Their developing bodies and minds make them more susceptible to the detrimental effects of noise.

The impact of noise pollution on stress is not limited to humans. Wildlife, including animals on land and in the ocean, also suffer from the negative consequences of unwanted noise. For example, loud noises have been shown to affect the heart rate and reproductive success of certain species.

The sources of noise pollution vary, with vehicles, aircraft, loud music, and industrial noise being among the most significant contributors. These sources can lead to chronic exposure, impacting the health and well-being of individuals, especially those in low socioeconomic areas.

The stress caused by noise pollution is a serious issue that can have far-reaching consequences for individuals, communities, and wildlife. It is important to recognise and address this issue to mitigate its impact on public health and the environment.

Hearing

Noise pollution, or environmental noise, is any unwanted or disturbing sound that affects the health and well-being of humans and other organisms. It is the second largest environmental cause of health problems, after air pollution. Noise-induced hearing loss (NIHL) is the most commonly discussed health effect of noise pollution.

Noise-induced hearing loss (NIHL) is the most common health effect of noise pollution. Approximately 10 million people in the US have permanent hearing loss from environmental noise or noise-related trauma. NIHL can manifest as abnormal loudness perception, tinnitus, and paracusis (distorted hearing).

Children are particularly vulnerable to the negative health effects of noise pollution, including noise-induced hearing loss. A 2014 study found that chronic exposure to noise for 8 hours a day could cause permanent hearing changes in children, including the inability to hear certain frequencies. The Indian Journal of Pediatrics notes that noise pollution can affect a child's hearing at any stage of development, including fetal, infancy, and adolescence.

In addition to hearing loss, noise pollution can cause hypersensitivity to sound. It can also lead to high blood pressure, heart disease, sleep disturbances, and stress, all of which can have indirect effects on hearing. For example, stress and lack of sleep can impact a person's mood and ability to concentrate, which may affect their ability to communicate and process verbal information.

The World Health Organization (WHO) has reported that environmental noise is among the top environmental risks to health, resulting in an estimated 1 million healthy years of life lost every year. The European Environmental Agency estimates that at least 20% of the EU population lives in areas where noise levels are harmful to health.

To protect against hearing loss, it is recommended to wear protective devices such as earplugs when exposed to high levels of noise pollution, and to have your hearing tested if you are experiencing hearing loss or ringing in the ears.

Cognition

Noise pollution has a significant impact on human cognition, affecting the ability to concentrate, memory retention, and learning.

The brain is constantly monitoring sounds for signs of danger, even during sleep. As a result, frequent or loud noise can trigger anxiety and stress, with continued exposure leading to increased sensitivity to stress. This heightened awareness can cause irritability, frustration, and anger, particularly if an individual feels they have no control over the noise in their environment.

Noise pollution can also impair cognitive performance, especially in children. A study by the American Speech-Language-Hearing Association (ASHA) found that aircraft noise alone resulted in an estimated 12,500 schoolchildren suffering from learning impairment. Noise pollution can interfere with speech and language development, decrease concentration, and impair memory retention.

The impact of noise on cognition is further exacerbated when individuals feel they cannot control the amount of noise in their environment. This sense of powerlessness intensifies the negative impact of noise pollution on mental health and well-being.

In addition to children, vulnerable groups such as those living in low-income neighbourhoods and communities of colour bear the brunt of noise pollution. These communities are often exposed to higher levels of noise, leading to adverse cognitive effects and other health issues.

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