‘Noise’ is distinct from ‘sound’ in that the term refers specifically to unwanted and/or harmful sounds. 

Noise can be more than just annoying – there have been studies linking chronic, low-frequency noise exposure points to an association with increases in disturbed sleep, stress, cardiovascular diseases, childhood development, and mental health (Hahad et al., 2019; Munzel et al., 2024; Basner et al., 2014).

Read on to learn more about health impacts, animal impacts, and noise measurement scales.

Noise pollution has been shown to correlate to adverse health effects such as hearing loss, sleep disturbance, impacted cognitive function, and increased cardiovascular disease (Baliatsas et al., 2016). A 2020 study in Europe found that long-term exposure to environmental noise resulted in about 48,000 new cases of ischemic heart disease and 12,000 premature deaths, though these numbers are likely to be underestimated (Peris et al., 2020).

Despite the US Environmental Protection Agency’s (EPA) recommendation of noise limits at 55 dBA for 24-hour exposure periods and a secondary limit of 70 dBA to prevent hearing loss, around 104 million Americans are exposed to levels above 70 dBA, which is around 1 in 3 Americans (Hammer et al., 2013). 

Chronic exposure to noise pollution has the potential to result in hearing loss (Basner et al., 2014). Hearing loss occurs when the auditory sensory cells in the cochlea are lost; these cells cannot regenerate in mammals, leading to a permanent loss of hearing (Basner et al., 2014). Hearing loss is caused either by a single exposure to an intense impulse sound or by constant, long-term exposure to sounds between 75 – 85 dB, the equivalent to a vacuum cleaner or lawn mower (Basner et al., 2014; CDC 2024). Globally, hearing loss affects about 1.3 billion people, and traffic-related noise accounts for a loss of more than 1.5 million healthy hearing years (Basner et al., 2014; Hahad et al., 2019). Tinnitus, which is ringing in ears, impacts quality of life and is caused by high-intensity or chronic exposure to noise (Basner et al., 2014). In 2019, hearing loss accounted for 2.24 million years lost to disability (YLD), with around 23% of the United States’ population having hearing loss (Haile et al., 2024). 

Sleep disturbance is another adverse health effect associated with noise exposure. Night-time exposure to noise pollution has a higher risk of long-term health effects than day-time exposure of noise pollution (Jarup et al., 2007). Sleep disturbance impacts the quality of sleep by lowering deep and rapid eye movements, increasing the time spent awake or in light sleep, and delaying the onset of sleep. Poor sleep impacts day-time functioning, performance, and mood and has been linked to an increased risk of hypertension and cardiovascular diseases (Münzel et al., 2024; Basner et al., 2014; Jarup et al., 2007). 

Noise pollution can also affect mental health and well-being, namely through a rise in annoyance, stress, and negative emotional responses. Annoyance relative to noise can arise from its disturbance and interference with daily activities, leading to anger, displeasure, and stress which cause a lowering in reported quality of life (Basner et al., 2014; Dratva et al., 2010). Stress caused by constant noise exposure is associated with cardiovascular complications (Hahad et al., 2019). Traffic noise has been linked to major depression and stress, which are known risk factors for developing coronary heart disease (Dhar and Barton, 2016; Münzel et al., 2024). 

Physiologically, noise can induce the body’s nervous system to release cortisol and catecholamines, which are stress hormones; thus, the risk of increased blood pressure, vascular dysfunction, and oxidative stress is heightened (Münzel et al., 2024; Münzel et al., 2017). The increase of stress hormones in turn increases the risk of developing cardiovascular diseases such as hypertension, stroke, ischemic heart disease, and myocardial infarction (Hahad et al., 2019). Thus, with noise pollution continuing to be a byproduct of data centers, the stress caused by continuous noise could lead to increases in negative long-term health effects.

For children, exposure to noise can have lifelong consequences including permanent hearing impairment and decreased cognitive performance. Hearing impairment and poor sleep has negative impacts on children’s communication abilities, ability to pay attention, and emotional regulation, which all lead to decreased learning outcomes (Basner et al., 2014). Additionally, children may be more likely to accumulate stress due to a potential lack of effective coping mechanisms (Basner et al., 2014). 

The impact of noise pollution spreads beyond humans; research shows that across animal species, the response to noise and chronic stress from noise is generally uniform; thus, excessive noise exposure will affect a majority of species concurrently (Kunc and Schmidt, 2019). In animals, noise can disrupt communication, homeostasis, and foraging abilities; additionally, noise pollution can lead to displacement of wildlife and lower reproductive success, which can put a strain on certain species (Kunc and Schmidt, 2019; Hemmat et al., 2023).

According to Cirrus Research, noise can be categorized as continuous, intermittent, impulsive, and low-frequency.

Continuous noise, such as that produced by factory machinery, engines, and HVAC systems, is noise that occurs continuously at approximately the same volume, tone, and frequency.

Intermittent noise is defined as noise levels that rapidly increase and decrease; examples of intermittent noise include passing trains and planes and machinery that operates cyclically.

Impulsive noises are sudden bursts of unexpected, and oftentime startling, noise such as gun shots, explosions, and construction noise.

Low-frequency noise, such as that from power stations and diesel engines, are the most difficult type to mitigate and can travel for miles (Cirrus Research). Exposure to low-frequency noise is common in today’s world, especially in urban environments (Berglund and Job, 1996).

Sound consists of longitudinal waves moving through matter, including solids, liquids, and gases. In air, these sound waves are made up of alternating high-pressure and low-pressure regions as particles compress and then spread apart. The frequency of a sound, measured in Hertz (Hz), refers to the number of wave cycles that occur per second. Differences in frequency are perceived by the human ear as differences in pitch, with higher frequencies being perceived as higher-pitched sounds. Humans typically are able to perceive sounds with frequencies ranging from 20 to 20,000 Hz. Learn more at the Encyclopedia Britannica.

Sound intensity is measured in decibels (dB), which operate on a logarithmic scale; this scale more accurately represents how changes in sound intensity are perceived as changes in loudness by the human ear (How is sound measured?, 2025). 

The A-weighted decibel scale (dBA) is commonly used when discussing safe and dangerous listening levels because it takes into account the intensity and frequency of a sound, as well as what the human ear can perceive. For example, low frequency sounds below the range of typical human hearing will produce a lower dBA reading than a dB reading because the ear does not perceive the frequency of the sound effectively (How is sound measured?, 2025). 

The widespread use of the A-weighted decibel scale by regulatory bodies leads to understating of noise impact when a majority of the noise is low frequency.  According to the World Health Organization, because low frequency sounds are weighted as “less important” than mid- and high-frequency sounds (Berglund et al., 1999, p. viii), “when prominent low-frequency components are present, noise measures based on A-weighting are inappropriate” (Berglund et al., 1999, p. xiii). Previous experiments have illustrated this effect, showing that the A-weighted scale underestimates the loudness and annoyance of low-frequency sounds. Studies by Kjellberg et al. (1984) and Nilsson (2007) both found that sounds at the same or similar dBA levels were deemed louder and more annoying by participants when they consisted of more low-frequency components. 

The A-weighted scale’s failure to capture perceived loudness and annoyance may lead to harm. With regulations often using dBA to set sound level limits, low-frequency noises that fall within these limits may escape scrutiny despite leading to negative health consequences.