A Comprehensive Review of Auditory and Non-Auditory Effects of Noise on Human Health

Abstract

Objective:

Excessive noise is unpleasant and induces several physiological and psychological effects. Noise pollution is a potential threat to humans, particularly those continuously exposed for extended periods throughout the day over many years. This review aims to examine the various auditory and non-auditory outcomes associated with prolonged exposure to noise pollution.

Materials and methods:

The review utilized a combination of relevant keywords to search the electronic databases. After screening based on the applied selection criteria for title, abstract, and full text, 44 articles were finally selected for critical review.

Results:

We identified and analyzed research findings related to noise-induced hearing loss, tinnitus, and sleep disturbances along with non-auditory issues such as annoyance, cognitive impairments, and mental stress associated with cardiovascular disorders. Furthermore, the existing studies were compared and collated to highlight the unique challenges and significance of noise pollution as a distinctive environmental concern and to explore the ongoing efforts in its research and prevention, including the early detection and potential reversal of noise-induced hearing loss.

Conclusion:

The fundamental health consequences of noise pollution underscore the need for extensive research encompassing emerging noise sources and technologies to establish a health management system tailored to address noise-related health concerns and reduce noise exposure risk among populations. Finally, further research is warranted to ensure improved measurement of noise exposure and related health outcomes, especially in the context of occupational noise.

KEY MESSAGES:

• A vital comprehensive review of the intricate connection between noise and diverse health outcomes, including auditory and non-auditory effects.

• Occupational noise poses a risk to the hearing health of workers, particularly those in the mining and transportation sectors.

• Early detection and intervention for noise-induced hearing loss and exploring treatment methods such as cochlear implants are crucial.

• Noise pollution significantly increases annoyance, sleep issues, and cardiovascular health risks.

INTRODUCTION

Comparing noise pollution with other forms of pollution, such as that of air, water, and land is generally considered inappropriate. This situation is solely because of the adverse effects of air, water, and land pollution that have been extensively documented and well established. However, noise pollution requires a broader examination due to its unique characteristics and effects on human health. In contrast to other types of pollution, an environment becomes clear of noise pollution as soon as the relevant noise ceases. As per a report from World Health Organization (WHO), noise pollution ranks as the third most hazardous form of pollution, falling below air and water pollution.[1] Noise is defined as an environmental stressor that reduces the quality of life and overall well-being. Moreover, excessive noise disrupts communication between individuals and mental concentration and triggers emotional reactions, including noise annoyance.[2,3] The rapid urbanization and evolving lifestyles have made loud noise an integral aspect of life, with the resulting indoor and outdoor environmental noise pollution posing a substantial health risk. Additionally, the escalating adverse effects of noise pollution have been observed among individuals of all ages, including fetuses, infants, children, adolescents, and adults.[3] Extensive research indicates that prolonged exposure to elevated noise levels is linked to a range of non-auditory effects, including mental health issues such as anxiety and depression, increased hypertension risk, disturbances in hormonal function, adverse outcomes during birth, sleep disorders, and high blood pressure-associated cardiovascular disease (CVD).[2,4] Bustaffa et al.’s[5] study concluded that noise exposure may indirectly lead to stress, promote psychological symptoms and disorders, and contribute to brain and cardiovascular disturbances. Similarly, a recent cross-sectional study of 1005 state government employees in Malaysia provided evidence supporting the link between occupational noise exposure and hypertension risk, demonstrating a hypertension prevalence of 18.8% among noise-exposed workers.[6] This study is one of the few studies in the ASEAN region investigating the link between occupational noise and hypertension, considering the cultural and lifestyle differences. Furthermore, Owolawi[7] proposed that continuous exposure to noise levels ranging from 85 to 90 dBA, especially over the lifetime of an individual in industrial settings, could cause a reduced hearing perception that results in hearing loss and a heightened hearing sensitivity threshold.

Although noise pollution is frequently overlooked compared to other more visible environmental challenges, it remains a pervasive and growing concern that warrants our attention, inventive solutions, and united dedication to its mitigation. In the following sections of this review, we will uncover the factors contributing to noise pollution, discuss the hazardous outcomes of noise pollution on human health, cognitive processes, society, and well-being, and highlight its mitigation measures.

Sources of Noise Pollution

A thorough investigation of the origin of noise pollution is crucial in devising effective strategies to diminish its effects. The various factors responsible for noise pollution, including natural and human-made sources, are delineated below.

Industrial Machinery: Noise within industrial settings originates from various processes that cause impact, reciprocation movement, vibration, friction, and turbulence in air/gas streams.[8]

Construction Noise: Construction noise has a sudden, non-permanent nature, high intensity, challenging control, and limited duration, ultimately exhibiting significant effects on urban residents.[9,10] The major sources of construction site noises include knocking, hammering, piling, welding, and material transportation.[11]

Rail Traffic: Railways are a prominent noise source, contributing a high concentration of noise in a relatively short time and posing a potential danger to human health. The key factors leading to noise generation from railways include train frequency, train speed, condition of railway tracks, and intensity of train horns.[12]

Air Traffic: Aircraft noise is characterized by its intermittent nature, with successive noise events typically separated by a period of silence. During take-off, the primary noise source is aircraft engines, whereas aerodynamic noise produced by the flaps, gears, and other components may become more pronounced during the landing phase.[13]

Road Traffic: This is the primary contributor of community noise, with noise levels often rising in proportion to increasing traffic volumes. Noise pollution from road traffic depends on several factors, including traffic volume, car speeds, and the presence of heavy vehicles and motorcycles. In low-speed vehicles, the major source of noise pollution is the mechanism responsible for power transfer. Vehicle tires become the predominant source at speeds exceeding 30–50 km/hour whereas aerodynamics results in noise emissions at speeds surpassing 80 km/hour.[14,15] Although noise pollution in urban areas originates from diverse sources mentioned above, vehicle traffic remains the primary contributor, leading to physiological effects that contribute to the overall disease burden. On a global scale, road traffic noise is a critical environmental pollutant, with conservative estimates suggesting an annual loss of about 1 million healthy life years in Western Europe.[16]

MATERIALS AND METHODS

This comprehensive review intends to thoroughly examine the existing literature on the harmful effects of noise exposure. We searched multiple electronic databases, including PubMed, Web of Science, and Scopus to identify relevant publications using keywords like, noise pollution, noise assessment, hearing loss, noise exposure, traffic noise, urban noise, industrial noise, recreational noise, mental health, noise annoyance, impact of noise on health, audiometry, sleeping disorder, and noise mitigation. Our initial search detected 350 articles. Two authors (AM & MM) independently evaluated all the titles and abstracts identified from the database according to the inclusion criteria. Discrepancies between the authors were resolved through mutual consensus. All the articles as well as their references were reviewed and assessed. Finally, 44 articles were critically reviewed. Figure 1 displays the literature search and selection process. We specifically sought articles that were cross-sectional studies, surveys, meta-analyses, and cohort studies. The inclusion criteria were as follows: (a) occupational or environmental noise exposure, (b) related health outcomes, (c) original article, and (d) publication in a peer-reviewed journal. The exclusion criteria were as follows: (a) studies published before 2019 and (b) studies reporting hearing loss caused by other factors. Majority of included studies were of cross-sectional nature because we believed that these studies provided assessment across diverse populations and identified at-risk groups for further investigation. This review focused on latest studies published within the last five years up to December 2023.

Figure 1.

Literature search and selection process using PRISMA. (Drawing software: Microsoft Visio, Verion: 2021, Manufacturer: Microsoft Corporation).

HEALTH HAZARDS OF NOISE POLLUTION

Apart from hearing-related issues, noise pollution potentially causes other health problems such as sleep disturbance, nervous sensitivity, muscle cramps, change in blood pressure, and physical and mental fatigue, as reported by Munzel et al.[17,18] Noise is also identified as a cardiovascular risk factor owing to its association with conditions including arterial hypertension, arrhythmia, coronary artery disease, and heart attack.[19] In addition to its auditory effects, noise may exert non-auditory effects on the human body, encompassing consequences on the health and well-being that arise from noise exposure and excluding the impacts on the hearing system and issues caused by the masking of auditory information, such as communication difficulties.[20] In this section, we explore the various effects of noise pollution, broadly categorizing them into auditory and non-auditory noise effects.

Auditory Effects of Noise

Noise has a range of auditory effects on humans, depending on its intensity, duration, frequency, and individual sensitivity. The major auditory effects of noise are described below.

Hearing Loss: An individual has hearing loss when he/she cannot perceive a sound audible to another individual in the same environmental conditions. This can be either temporary or permanent, with the nature of the loss often depending on the noise intensity and duration. After an individual is exposed to an extremely high noise level, he/she may experience a temporary shift in their auditory threshold that can lead to reduced hearing. This shift may induce temporary hearing loss. However, this effect is usually reversible and the person’s hearing capability returns to normal after a period of rest in a quieter environment. In contrast, prolonged and frequent loud noise exposure may result in a permanent threshold shift, possibly causing permanent hearing loss.[21] Auditory effects comprise hearing loss and deafness. Moreover, depending on the impairment severity, hearing loss can be categorized as slight, moderate, or severe. Hearing loss may occur in either one or both ears. Individuals who are hard of hearing experience mild-to-severe hearing loss, while those who are deaf typically have severe hearing loss, with minimal or no hearing ability. Furthermore, sustained exposure to high-intensity noises, such as those originating from industrial settings or heavy machinery, may lead to permanent hearing loss, a condition termed as noise-induced hearing loss (NIHL). A research conducted on NIHL indicated that long-term exposure to loud noises triggers irreversible damage in the sensorineural structures of the cochlea, particularly the sensory hair cells. Consequently, this damage may reduce an individual’s attention during work, contributing to accidents and falls and increasing the risk of injuries and fatalities.[22] According to the WHO report on hearing released on 2 March 2021, hearing loss currently impacts >1.5 billion individuals globally. Among them, 430 million individuals are suffering from moderate or more severe hearing loss in their better hearing ear, rendering them particularly susceptible to adverse effects unless the condition is promptly addressed.[23] Additionally, the report projects that approximately 2.5 billion individuals worldwide may present with some form of hearing impairment by 2050, with about 700 million individuals seeking treatment for this condition. Occupational NIHL predominantly affects both ears. Another distinctive feature of this type of hearing loss is a notched pattern on the audiogram, often observed at high frequencies of 3, 4, or 6 kHz. Interestingly, individuals with this hearing loss may exhibit some hearing improvement at 8 kHz.[24]

Tinnitus: Tinnitus is a condition that occurs after exposure to loud noise and is characterized by the triggering of ringing or hissing sensations in the ears. It may be temporary or chronic and can substantially affect an individual’s quality of life. This condition arises from injury to the delicate hair cells located in the inner ear.[25] As per a latest investigation by Vasilkov et al.,[26] chronic tinnitus leads to reduced cochlear nerve responses, poor muscle reflexes of the middle ear, and increased hyperactivity in the central auditory system.

Hyperacusis: Some individuals may develop hyperacusis, a condition in which they become extremely sensitive to even moderate noise levels. Thus, individuals with this disorder may experience discomfort or pain when exposed to sounds that others perceive as normal.[27] In this context, research conducted by Ren et al.[28] compiled the findings of 42 studies, involving a total of 34,796 participants across different populations including 28,425 general population, 2,746 participants of special occupation and 5,093 concomitant patients. The research revealed that the occurrence of hyperacusis across different studies, ranged from 0.2% in 9-year-old children to 17.2% in adults of general population, whereas it increased from 3.8% to 67% in musicians and 4.7% to 95% in special patients. Moreover, hyperacusis was prevalent among adolescents and older adults, with women being more prone than men. The research also identified conditions including Williams syndrome, tinnitus, and autism, as high-risk factors for hyperacusis.

Communication Difficulties: Noise can interfere with effective communication, especially in settings such as classrooms, workplaces, and public spaces where clear speech is crucial. In such situations, people may be required to raise their voices to be heard, further contributing to overall noise levels. Researchers have examined that individuals often face difficulty in understanding speech in noisy environments, especially in industrial settings, potentially leading to increased frustration and reduced productivity.[29,30]

Auditory Fatigue: Auditory fatigue may be induced by continuous exposure to certain types of noises, such as constant background noise in a busy environment. This phenomenon may result in a temporary reduction in a person’s ability to perceive sounds accurately. An investigation by Venet et al.[31] identified various factors causing auditory fatigue in music professionals exposed to amplified music, aiming to determine the primary parameters influencing auditory fatigue during occupational exposure. their investigation involved 43 music exposed adults and 24 unexposed administrative agents. Results showed that changes in pure tone average (ΔPTA) and efferent reflex thresholds (ΔER) were positively correlated with noise energy and its stability, indicating that steady noise contributes more to auditory fatigue. They proposed integration of quite periods, reducing music levels, and using hearing protection to alleviate auditory fatigue.

NIHL has a significant global role in hearing disorders, affecting over 450 million people worldwide, that is over 5% of the global population. In adults, disabling hearing loss is described as a hearing loss >40 dB in the better-hearing ear. As per WHO, approximately 30% of individuals aged >65 years have disabling hearing loss.[32] NIHL progresses rapidly during the early years of exposure, with maximum damage occurring within the first 10 years of exposure and its characteristic notches visible at 3, 4, and 6 kHz. Subsequently, NIHL spreads to lesser frequencies with the increase in years of exposure.[33] Moreover, NIHL has numerous consequences and causes psychological effects as well. Some effects associated with NIHL include social isolation, difficulty in communication with co-workers and family, anxiety, irritability, decreased self-esteem, and diminished productivity.[34] Governments and certain organizations often establish noise regulations and guidelines to protect individuals from excessive noise exposure in various settings. A recent review underlined the multifaceted impact of NIHL on individuals and society, emphasizing preventive measures such as hearing protection in loud settings and governmental regulations. According to this review, although experimental therapies are promising for immediate treatment, they fail to address chronic NIHL.[35] A cross-sectional study in Gondar city, Ethiopia, reported 30.7% occurrence of hearing loss among metal workshop workers. Features such as age, cigarette smoking, noise levels >85 dB, and longer work experience were highly associated with increased risk of NIHL, while using ear protection devices lowered the risk.[36]

NIHL has been examined across various professions, including drivers who experience hearing loss due to various factors such as noise generated by the vehicle’s engine and the loud urban environment. An investigation into the prevalence of hearing loss in 65,533 truck and bus drivers reported significant hearing loss in 26.8% of them, with a notable disparity between the left and right ears.[15] Another cross-sectional study assessed the auditory conditions of commercial and non-commercial drivers of light motor vehicles in Lucknow, India.[37] The study used a medical grade MAICO Audiometer (MA42) to conduct pure tone audiometry of the drivers at various frequencies. The findings revealed that the mean hearing thresholds of group I (autorickshaw drivers) at the lower frequencies of 0.25, 0.5, 1, and 2 kHz were 16.23 ± 11.94, 20.70 ± 12.19, 18.20 ± 12.45, and 25.73 ± 12.24 dB, respectively. Additionally, the mean hearing threshold of group I at the higher frequencies of 3, 4, 6, and 8 kHz were 31.07 ± 14.78, 34.97 ± 15.23, 30.37 ± 17.38, and 30.87 ± 19.97 dB, respectively. The study also revealed that 34.7% of the participants in group I (autorickshaw drivers) and 2.67% of those in group II (car drivers) had a mean hearing loss >25 dB. The findings proposed the need of raising awareness and educating the general population about the detrimental effects of NIHL. Corresponding results were also demonstrated in a study that employed a 19-item questionnaire to assess the hearing health of 245 students from three universities in Jordan. The study showed that 58% of the students had hearing symptoms, even though 9.8% of them had reported using earplugs.[38] According to earlier studies, NIHL has the highest prevalence among heavy vehicle drivers in the mining sector (61%).[39] This observation was further substantiated by an audiometric investigation of the hearing loss risk factors in 28 dozer operators at a gold mining company. According to the study, all the dozers exceeded the threshold limit value for noise exposure. Furthermore, about half of the dozer operators exhibited standard threshold shift hearing loss, particularly those aged ≥40 years and with >5 years of experience, inadequate use of personal protective equipment (PPE), and habits such as listening to music and smoking. These results underscore the significance of addressing noise and demographic factors to mitigate hearing loss risks among dozer operators.[40]

Research on recent developments in NIHL and tinnitus has indicated that permanent hearing loss may develop from exposure to noises exceeding 89 dBA for >5 hours per week.[41] Moreover, the studies suggested that noise-related damage was not completely reversible, while NIHL could be prevented with treatment methods such as cochlear implants, pharmacologic therapy, antioxidants, and tinnitus management. Other than occupational noise, Neitzel & Fligor[42] reported that recreational sound exposure could also pose a potential risk for hearing loss. They further proposed a noise exposure limit of 70 dB for recreational sound in the case of vulnerable individuals and a 75 dB limit for others over an exposure period of 40 years.

Occupational noise exposure is not restricted to individuals working in the transportation industry. It is prevalent among individuals in all places and industries with noisy environments or backgrounds. Kanji et al.[43] investigated the effect of noise exposure on occupational workers in gold and non-ferrous mines. Their research revealed that most of the participants (97%) accepted that they were working in noisy conditions and were aware of its potential impacts. Additionally, most of the participants knew the value of hearing protection devices (HPDs), <50% of them reported using HPDs. Another study examined the impact of noise exposure on power plant workers in N’Djamena, Chad.[44] The study involved 92 workers (88 men and 4 women; age range: 23–64 years). The researchers found that the workers in the machine rooms were exposed to an average noise level as high as 113.5 ± 4 dBA over an average duration of 10.8 ± 8.5 years. Although 85.9% (n = 79) of them regularly wore PPE, many experienced adverse effects such as auditory fatigue (38%), nervousness (45.7%), hearing impairment (15.2%), tinnitus (32.6%) and insomnia (14.1%). These findings highlight the need for regulating the noise levels of machinery and integrating audiometric testing in employee follow-up assessments to minimize the detrimental health impacts of occupational noise.

Non-Auditory Effects of Noise

The non-auditory effects of noise include annoyance, sleeplessness, communication interference, behavioral disorders, and cardiovascular complications. Noise-related annoyance may have broader effects on various aspects of daily activities, disrupt sleep patterns, and cause restlessness. It may also trigger various responses, including feelings of anger, displeasure, tiredness, and stress, in affected individuals. Although these factors may appear temporary, they can take a toll on human health in the long run. Hence, non-auditory effects are manifold and have serious effects on human health. Nevertheless, mitigating environmental noise exposure can help alleviate these health effects. Some non-auditory effects such as high blood pressure, sympathetic nervous system stimulation, and stress hormone release may alter physiological parameters including, blood clotting mechanism, cardiovascular function, and levels of blood sugar and cholesterol.[45] Individuals living in high-rise buildings are also exposed to traffic noises. In line with this notion, Jensen et al.[46] demonstrated a link between noise-related annoyance and a higher likelihood of experiencing mental health challenges and increased stress levels among individuals living in multistorey housing.

Significant research emphasis has been placed on the health outcomes resulting from noise exposure. Several studies are being conducted to ascertain the degree of noise effect using different scales and methods. A recent investigation sought to establish limits of occupational noise exposure for reducing non-auditory effects in normal males by utilizing exposure-effect regression models based on laboratory and field data. In the study, equivalent noise levels were measured in various work settings, and the levels ranged from 65 dBA in closed offices to 80 dBA in industrial workplaces. Psychophysiological parameters were also recorded during exposure to noise levels exceeding 55 dBA, with variations observed above 70 dBA. Further, the regression models successfully predicted noise-induced psychophysiological responses, suggesting an acoustic comfort limit below 55 dBA, acoustic safe limit at 55–65 dBA, acoustic caution limit at 65–75 dBA, and occupational exposure limit above 80 dBA.[47]

Sleeplessness: Noise significantly influences sleep and can result in sleeplessness or insomnia. Noise adversely affects sleep quality by causing difficulty falling asleep (sleep onset disruption), resulting in sleep fragmentation and interrupted sleep cycles. Noise disruptions can lead to reduced rapid eye movement (REM) sleep, characterized by dreaming and cognitive rejuvenation, which in turn affects memory consolidation and emotional regulation. Adequate sleep for an average of 6–8 hours is crucial for the overall health of adults, and sleep deprivation can potentially result in fatigue. Outdoor noise is one factor that may lead to insomnia, wherein people with insomnia report feeling sleepy even during work hours. This sleep disorder can cause changes in an individual’s lifestyle and severe stress. Sleep deprivation may also result in sleep apnea, characterized by intermittent breathing patterns, loud snoring, and a feeling of tiredness even after full sleep.[48,49] Urban noise exposure is increasingly prevalent, yet its effects on sleep are debated. To address previous research limitation, a field study conducted horizontal and longitudinal analyses in urban homes. Over 1050 test nights in 75 households, noise was monitored alongside sleep quality assessments via actigraphy and questionnaires, providing insights into the relation between urban noise and sleep. The study reported that 92.3% of bedroom environments did not meet the standards, with 87.9% experiencing harmful noise. Both physiological (e.g., REM sleep duration) and psychological (e.g., subjective sleep quality) aspects were affected by noise intensity and perception. Women showed greater sensitivity, particularly in emotional responses. The findings emphasize the need for better bedroom acoustic design in cities and highlight the importance of addressing anxiety related to noise exposure.[50]

Additionally, Roosli et al.[51] reported that outdoor noise may cause increased sleep latency, a sleep problem in which individuals require a longer time than usual to fall asleep. Furthermore, their research revealed that sleep latency increased by approximately 5.6 minutes with 95% confidence interval [CI]: 1.6–9.6 minutes, for every 10 dBA increment in noise levels during the initial sleep hour. Correspondingly, sleep efficiency significantly decreased by 2–3% for every 10 dBA rise in measured outdoor noise (equivalent continuous sound level, L_eq over 1 hour) during the last 3 hours of sleep.

A meta-analysis examining the impact of hearing disability on sleep quality in industrial workers revealed a 30% prevalence of related issues (95% CI: 25–35%). Men had a prevalence of 38% (95% CI: 31–45%), whereas women had a prevalence of 32% (95% CI: 14–50%). Moreover, the prevalence rates were: 36% in poor sleep quality, 22% in insomnia, 37% in shorter sleep duration, 29% in snoring, and 10% in sleepiness.[52] Another study presented alarming statistics highlighting a 20% reduction in sleep rate among insomniacs and high prevalence rate of insomnia, reaching to 30% among the investigated individuals. These findings were linked to stress, a propensity to seek medical assistance, and an association with weight gain risk.[53]

Yamagam et al.[54] reported on the association of indoor noise during night with objective and subjective sleep quality in the older people, involving 1,076 participants aged ≥60 years. They utilized multivariable linear regression models to observe the effect of indoor noise levels on various sleep parameters. The findings indicated a significant fall in objective sleep quality measures for every 1 dB increase in noise level. These measures include increased wake after sleep onset, poor sleep efficiency, extended sleep onset latency, and increased fragmentation index. The research underscores the significance of noise reduction interventions to prevent adverse health outcomes due to poor sleep quality in older adults.

Annoyance: Pervasive noise exposure, particularly in urban settings, may escalate annoyance levels, thereby affecting an individual’s concentration, sleep, and communication and consequently leading to increased irritation. Transportation noise and the resulting annoyance may also lead to depression, especially in individuals who are not physically active or those experiencing daytime sleepiness. According to a Swiss cohort study involving 4,581 participants, noise-related annoyance further aggravates poor mental health.[55] All these findings illustrated a clear association of transport noise levels and annoyance with an increased depression risk. Additionally, older individuals may be more likely to experience annoyance in a noisy environment than younger people exposed to the same noise levels. Individuals sensitive to noise are also more prone to feel irritated and annoyed in a noisy atmosphere. Moreover, noise annoyance may be influenced by individual factors, including age, health status, stress management abilities, noise duration, the extent and frequency of noise exposure, noise source, and sensitivity towards noise.[56,57] A study explored the effects of environmental noise annoyance on psychological distress and sleep issues in 822 adults in Tehran, Iran. The study utilized noise exposure indicators along with the Pittsburgh Sleep Quality Index (PSQI) questionnaire and the Kessler Psychological Distress (K10) scale for assessing the frequency of sleep disturbances and psychological distress, respectively. The results revealed that the study population had high levels of noise sensitivity and significant associations of noise annoyance at home and workplaces with psychological distress. Furthermore, the researchers stressed the potential consequences of non-standard noise levels on physical and mental well-being.[58]

In another study by Tao et al.,[59] the mobility of an individual and the passage of time were shown to alter the connection between noise exposure annoyance and psychological stress. This observation underscores the significance of considering the real-time noise, its spatiotemporal dynamics, and subjective responses in health impact assessments for urban planning and management.

Rasmussen & Ekholm[60] have reported on another aspect of noise annoyance, that is neighbor noise annoyance. In their study, the authors surveyed 3,893 respondents residing in multistorey housing and demonstrated that 36% reported neighbor noise annoyance and 22% experienced traffic noise annoyance. Although causality could not be confirmed, strong associations were detected among neighbor noise annoyance and psychological well-being. Hence, the adverse impact of neighbor noise on health and sleep warrant greater attention, like those of traffic noise.

In this context, Okokona et al.[61] also conducted a comprehensive survey of 7,321 respondents to evaluate the impact of noise annoyance on psychotropic medication. They found that 15% of the participants were on sleep medication, 7% on anxiolytic medication, and 7% on antidepressant medication. The survey results also indicated a potential association between noise levels >60 dB and the use of antidepressant medication. Furthermore, another study was undertaken in areas of Sao Paulo, Brazil, where the noise levels exceed 55 dB, aiming to explore the link between residential exposure to traffic noise and annoyance levels in the context of noise perception and sensitivity. The results showed that approximately 48.4% participants experienced noise-related annoyance, highlighting the impact of traffic noise as a crucial health problem.[62]

Communication Interference: Although human inventions have enhanced the quality of life, they have exerted a gradual but significant cost on the environment and even led to its degradation. Noise interference in speech communication as an effect of environmental sound pollution has been recognized relatively late. Nevertheless, this concern has gained research attention in the last decade. The major factors contributing to noise-related communication interference are noise levels, proximity between the speaker and listener, and age. Meral & Konukseven[63] compared the effects of noise on speech intelligibility and memory capacities between young and older individuals, having no complaints of hearing issues. In this study, the researchers employed the Turkish matrix sentence test as well as short-term memory and working memory assessments in quiet and noisy conditions. Older participants showed poor performance in memory tasks and speech intelligibility, particularly in the noisy environment, suggesting an age-related decline in memory and increase in noise sensitivity. These findings underline the significance of considering age-related factors in auditory and cognitive research.

In another sample study of adults aged 33–55 years, individuals reported having to be more attentive and concentrate harder when communicating in a noisy background. In all 50 participants were involved in the survey, out of which 45 participants performed the behavioral tasks. Overall, the results implied that background noise is a frequently encountered source of hearing difficulty among this population.[64]

Understanding speech in noise interference is a common challenge faced by individuals. In a research conducted to investigate how online changes in cortical arousal effect brainstem frequency-following responses (FFRs) during speech perception, electroencephalogram (EEG) measurements were obtained from older adults with normal hearing (NH) and mild-to-moderate hearing loss (HL) as they completed speech identification task in varying noise environments. The results showed reduced cortical arousal in the HL group and diminished cortical-brainstem modulation compared to NH individuals, particularly in noisy conditions. The findings suggest a probable explanation for the challenges older listeners face in understanding speech in noisy environments, indicating a possible disconnection between cortical and subcortical auditory processing levels.[65]

Another study aimed to explore the clinical pathway and available treatments for individuals with normal audiograms or mild hearing loss (NA-MHL) having trouble in understanding speech in noise. Analysis of data gathered from surveys and interviews involving 233 individuals with NA-MHL and 47 clinicians reported challenges in noisy environments, limited treatment options offered during audiology appointments, and frustration among clients upon being informed of their normal hearing status. Clinicians also expressed a lack of standardized testing protocols and training for this population. The results highlight the importance of conducting research and interventions aimed at improving the well-being of individuals suffering from NA-MHL.[66]

Studies have also promoted the utilization of hearing aids and cochlear implants in improving hearing quality and the quality of life. Hearing aids amplify sound, while cochlear implants enhance sound clarity and an individual’s ability to understand speech. Cochlear implants can be transformative by restoring hearing and instilling confidence in individuals who are deaf or severely hard of hearing. Research involving 45 adult recipients of cochlear implants with asymmetrical sensorineural hearing loss examined their performance in speech recognition and health-related quality of life (HRQoL). The consonant-vowel nucleus-consonant (CNC) word test and the AzBio sentence test in quiet and noisy environments with a signal-to-noise ratio of +5 dB, were performed on implanted ear. Additionally, HRQoL was assessed with the Nijmegen Cochlear Implant Questionnaire (NCIQ). The study findings indicated that cochlear implantation was beneficial among the participants investigated in the study.[67]

Humes & Dubno[68] conducted research to compare the perceived hearing difficulties among older adults from a community sample to two clinical samples, with and without hearing aid experience. Analysis of communication profile for the hearing impaired (CPHI) scale scores revealed significant differences between community and clinical samples, with severity of hearing loss and age affecting scores. Those with hearing aid experience reported greater communication difficulties but also greater acceptance of hearing loss compared to those without hearing aids, highlighting the impact of seeking assistance on perceived hearing difficulties.

Cardiovascular Disease: The severity of environmental noise is highlighted by its association with several health effects, of which CVD is a prominent condition that can even lead to death.[69] A comprehensive review encompassing 11 cohort studies with 224,829 participants revealed a significant association of increased hypertension risk with occupational noise exposure.[70] Another study investigated the prevalence of coronary heart disease (CHD) due to traffic noise, by conducting a subgroup analysis to identify the most susceptible population. The survey involved 909 adults (376 males and 533 females), and their traffic noise exposures were estimated using the L_den metric (day-evening-night noise level). The findings revealed a 2.25-fold increase in CHD risk for every 5 dBA rise in noise levels, with men being more susceptible than women. Subgroups with noise sensitivity, older age, high stress, and poor sleep quality showed elevated risk, suggesting that noise levels above 60 dBA were associated with CVD.[71] A latest study analyzed CVD mortality using data from five U.S. states by contrasting CVD mortality with mortality due to external causes. The study assessed long-term noise exposures from natural and human sources and found positive associations of CVD mortality with daytime and night-time anthropogenic noise, particularly in females, accompanied by monotonic trends up to a certain threshold of approximately 45–55 dBA.[72] A pooled analysis was undertaken by Pyko et al.[73] among 132,801 participants, examined the exposure-effect relationship between sources of transportation noise and ischemic heart disease (IHD) and its subtypes. The researchers observed that noise exposure in the previous five years was linked to high IHD risk, particularly after excluding angina pectoris cases, which were not well-documented.

According to research investigating the impact of environmental pollutants, specifically air and noise, the WHO indicates that genetic factors account for only 25% of the variability in longevity, with the remaining 75% determined by the physical and social environment. The research recognized them as crucial determinants of the ageing process. Noise was found to trigger a release of stress hormones through the hypothalamic-pituitary-adrenal (HPA) axis, thereby initiating immune system activation.[74]

Several epidemiological investigations have reported the harmful impacts of environmental noise. According to a latest umbrella review summarizing the findings of 23 systematic reviews, occupational noise exposure showed the highest risk increase for both speech frequency and high-frequency NIHL. Excessive noise exposure across various sources was related to 34% increase in risk of CVD and 12% in risk of death. Additionally, high noise exposure was linked to 58–72% increase in blood pressure, 23% increase in diabetes, and 22–43% increase in adverse reproductive outcomes. Furthermore, the results revealed a clear correlation indicating that as noise exposure levels increases, the risks of diabetes, IHD, cardiovascular mortality, stroke, anxiety, and depression are also increased.[75]

A systematic review proposed by Liu et al.[76] also indicated that workplace noise activates the sympathetic and hormonal systems, leading to stress hormonal secretion. The cardiovascular outcomes due to noise exposure and the necessity of a suitable mitigation strategy were also highlighted in the review. In support of these findings, a review by Hahad et al.[77] demonstrated the cerebral consequences of noise exposure, including hearing loss, neurodevelopment disorders in children, depression, anxiety, annoyance, stress and suicide, stroke, hypertension, dementia, and cognitive decline. Another survey involving the residents of Toronto (age range: 35–100 years) who possessed health insurance and had no history of hypertension, determined that prolonged traffic noise exposure was linked to increased rates of diabetes mellitus and hypertension.[78]

Impaired Concentration and Performance: Noise can affect cognitive functions such as concentration, memory, and problem-solving as well as hinder performance in tasks requiring focused attention. Additionally, chronic noise exposure may lead to increased stress levels, further impairing cognitive function.[59,79] Researchers examined 2,680 children of 7–10 years in Barcelona, Spain, to explore the effect of noise exposure due to road traffic at both school and home on cognitive development over a 1-year period, using the standard computerized cognitive assessments. The results suggested that higher traffic noise exposure at school, particularly noise level fluctuations inside classrooms, was linked to the slower development of working memory and attention, whereas traffic noise exposure at home showed no such significant association.[80]

RESULTS AND DISCUSSION

Noise is a serious public health concern due to its harmful effects on human life and health. The studies analyzed in this review collectively highlighted the significance of noise pollution across various domains, including roadways, railways, and airspace, and distinct occupational settings. NIHL affects millions globally, with pronounced consequences for individuals and society. Prior research suggests that even though experimental therapies show promise in treating NIHL, the management of chronic NIHL remains a challenge. Several studies have discussed the impact of noise on sleep quality and psychological well-being and identified traffic noise as a major concern. Residents exposed to traffic noise experience increased annoyance and sleep disturbances, emphasizing the importance of maintaining sound levels below 50 dB. Further, a high prevalence of sleep-related issues, including insomnia, has been observed among workers with prolonged noise exposure, underscoring the severe health consequences and associated risks of noise exposure. Additionally, noise exposure has also been linked to depression, especially in individuals with low physical activity. Lastly, the mental health outcomes of neighbor noise also warrant further attention. Nevertheless, the predominant focus in this research, as evidenced by most of the analyzed studies, is occupational noise exposure.

Noise is a manageable issue that can be reduced by collaborative actions across various societal and government levels, including incorporating smart city initiatives and utilizing real-time monitoring and data analytics for efficient noise management.[81,82] Some key strategies for mitigating noise pollution involve noise ordinances and urban planning with zoning laws, mandatory building codes to enforce the use of noise-reducing material, and the installation of sound walls and green buildings. Integrating green spaces, trees, and natural barriers into urban design can also serve as noise buffers. Other valuable strategies for reducing noise levels encompass advocating the utilization of public transport, emphasizing quieter modes of transportation (e.g. the widespread adoption of electric vehicles), and implementing noise reduction measures in the existing transportation system. Study conducted by Tsoi et al.[83] found that using electric buses reduced traffic noise levels in a densely populated city, achieving a noise reduction of up to 4.4 dBA during daytime. Moreover, the researchers indicated that electrifying the entire bus fleet could result in a noise reduction of 1 dBA in approximately 60% of the population, 1–2 dBA reduction in 15.3%, and >2 dBA reduction in 4.3%. Another way of reducing the traffic noise involves constructing low-noise pavements and installing noise barriers.[84]

Public awareness holds a pivotal part in addressing the issue of noise pollution. Therefore, awareness should be increased by educating the public about the adverse effects of noise on health, well-being, and overall quality of life. Furthermore, information campaigns can highlight the significance of responsible noise behavior at the individual and community levels.[85] Awareness campaigns are the most effective strategy for noise mitigation, along with government action to ensure adherence to regulations and policies on road traffic noise.

CONCLUSION

In this review, we describe the multifaceted impact of occupational and environmental noise on health across various sectors. Additionally, our review emphasizes the significant burden posed by noise pollution on public health, particularly in terms of hearing impairment, cardiovascular disorders, and mental health issues. We also underscore the importance of addressing noise pollution on various fronts, including occupational safety measures, urban planning, and environmental policies. In the quest for effective noise mitigation, future directions should focus on technological advancements, such as developing quieter machinery, vehicles, and equipment, to reduce noise emissions at the source. Moreover, the progress of innovative technologies, including the deployment of IoT sensors for real-time monitoring and subsequent analysis via AI algorithms, may enable city planners to identify high-noise zones. Intelligent urban planning not only involves technical innovations but also entails meticulously designing buildings and infrastructure, such as using materials that absorb or reflect sound and designing streetscapes to minimize noise propagation and significantly reduce noise levels. Finally, applying quantum acoustic sensors to create highly accurate noise maps of cities and to distinguish noise pollution sources with remarkable precision can aid in further reducing noise levels.

Consent to participate

All the authors have given their consent to participate in this research.

Financial support and sponsorship

Not applicable.

Conflicts of interest

The authors declare that there is no conflict of interest.

Ethics approval and informed consent

Not applicable.

Authorship contribution statement

AM: conceptualization, methodology, literature search (screening, selecting, and extracting data from studies in review), manuscript original draft, review and editing. SPS: conceptualization, methodology AKS: conceptualization, manuscript review. MKM: conceptualization, supervision. SKS: conceptualization, supervision. MM: literature search, manuscript writing, review and editing.

Guarantor: Anupam Mehrotra.