Noise level limits in different categorized areas of the city (Pakistan).
Noise pollution has been recognized as one of the major hazard that impacts the quality of life all around the world. Because of the rapid increase in technology, industrialization, urbanization and other communication and transport systems, noise pollution has reached to a disturbing level over the years which needs to be studied and controlled to avoid different health effects like high blood pressure, sleeplessness, nausea, heart attack, depression, dizziness, headache, and induced hearing loss. To address this situation, different countries have different strategies like vehicular noise limits and their regulation, vehicles physical health checkup, different time of operations for noisy traffic like trucks in the evening or night time, and noise pollution fines for noisy vehicles.
- traffic noise
- community effects
- human health
A sound is termed as noise when it becomes continuous and above the threshold limits of the ears . A vehicular noise is the resultant of the vibrating body of the vehicle plus its engine operating sound . Noise has different types including impulsive noise, continuous noise, intermittent noise and low frequency noise. All above mentioned types of noise are dangerous to human and animals if their limits are exceeded . Noise affects people so badly that at some places policy makers were compelled to said that there should be restrictions on noisy vehicles for reducing noise pollution as in New Delhi, India  and Guangzhou district, China . Noise is a common problem in urban areas as compared to the villages because of the mechanization and more vehicles on the road [6, 7]. All types of noise altogether affect the same irrespective of the sources and cause headache to the high blood pressure and other heart diseases . Some noise types like aircraft and train noise also has the negative effects on property prices [9, 10]. The noises from cracks in a refrigerator, fan and air conditioner affects evenly as a loud noise of train or aircraft because of its continuity. These results were obtained by a study that the noises in household appliances operations are one of the main sources of noise . It is one of the big problems in industrial areas. It is produced from mechanical operations, transportation vehicles and different sirens within the industry . Noise also disturbs mining worker and their operations . Due to this noise, workers face different health issues including hearing loss, dizziness, headaches, high blood pressure and anxiety [14, 15]. It is a fact that noise in the vicinity of airports is a public health issue and its exposure affect sleep quality, restlessness and headache . This noise also increases vascular and cerebral oxidative stress and triggers vascular dysfunction [17, 18]. In addition to the above, cargo ships are also the source of nuisance and sleep disturbance. However, these are usually not sources of noise as they affect only small communities living in harbors . Low frequency noise is also included in the noise types and effects humans by annoyance and sleep disturbances . Migraines, tinnitus, nausea, sleep disorders, insomnia, quality of life and minor stress strokes are the result of low frequency noise . Household and community noise is also a health issue. As we live in houses for the major part of the day and we are exposed continuously to different noise types like lawn mower noise, dogs barking, kitchen grinder operation and sound systems/television which seems dangerous. It is given in the documented form that there is an association with several diseases and the growing number of exposed persons all over the world with this type of noise. The effects are ranged from cardiovascular diseases to metabolic disorders [22, 23]. It also has impacts on animals including frogs to the whales and elephants by affecting their reproduction, communication within and with environmental factors, habitat loss and even death , and plays important role in geographical distribution of these animals .
From all above discussion, it can be clearly seen that health effects of the noise are common as hypertension, myocardial infarction, stroke, mortality, dizziness, high blood pressure and cognitive diseases, irrespective of the noise sources, suggesting the control of all the noise sources . To control the noise, different methods and equipment are made to control or minimize noise from different places like hospitals, educational institutions and workplaces . Adaptive noise control, , active noise control, , shelter belts , equipment and home insulations  and active vibration noise control devices are made for this purpose and to reduce the risks of noise .
2. Sources of noise pollution
Noise pollution has many sources of which the traffic noise could be a major source. Other types include community noise, household, industrial, aircraft and ships noise [33, 34, 35, 36, 37, 38, 39, 40, 41].
2.1 Traffic vehicles
Traffic noise, as depicted by the name, is the noise originated from the traffic vehicles specially the old vehicles with no maintenance and those vehicles which have not been physically cleared to be driven on the roads. Heavy traffic vehicles also contribute in noise generation due to their heavy engines and load [42, 43]. Traffic noise represents the important environmental risk factors in mechanized areas  and it is one of the fastest growing and most ubiquitous types of environmental pollution . It is associated with high blood pressure, but the long-term impact may lead to hospitalization and rare chances of death. In a study among London’s 8.6 million residents, traffic noise was associated with cardiovascular defects in all adults (≥25 years) and the elderly (≥75 years). It shows that long-term exposure to road traffic noise increases the risk of death and the risk of cardiovascular disease in the population .
2.2 Commercial and Industrial noise
Different commercial activities like transportation of goods from one place to other using ships and heavy trucks create considerable noise in the respective areas. Ocean noise levels are increasing as a result of major growth in global trading activities which shows that if this activity continued to grow, which is by 1.9% each year, the contribution of commercial shipping to ambient ocean noise levels will be expected to intensely increase . In addition to the ships, commercial aircrafts are also contributors in commercial and industrial noise. The main source of noise in aircrafts is the engine which generates more noise if the load on it is more [47, 48]. It is a well-known fact that all the machines produce noise and it is called as industrial noise. Different industries have different machinery like textile industry, wood industry and steel mills .
To assess the industrial noise effects on workers, all the workers of an industry in Jordan were included in a study. A structured questionnaire was used to collect data. Results revealed that out of total 191 workers, 145 (exposed to higher noise levels) had the issues of hypertension compared to those exposed to noise level lower than the permissible limit indicating that exposure to high level of noise is associated with elevated health risks .
2.3 Community noise
Community noise comprised of the noise during a match in the ground, traffic vehicle noise during waste collection, children playing in the streets, dogs barking, and noise during parties . Musical instruments being played can also be a source of noise for someone not interested in music [52, 53]. One study assessed the noise and noise sensitivity of 364 adults living in the South African community and compared them with similar studies conducted in Switzerland. Compared to Swiss research, the proportion of people with high levels of noise sensitivity is higher (women: 35.1% vs. 26.9%, men: 25% vs. 20.5%), people are very angry about road traffic noise (women: 20, 5% compared to 12.4%; male: 17.9% vs. 11.1% were observed in South Africa). Although women in South Africa are more averse to community noise than Switzerland (21.1% vs. 9.4%), this is not the case for men (7.1% vs. 7.8%), suggesting that the noise pollution can seriously affect the inhabitants of the population noise .
2.4 Air craft noise
Airplanes such as army, navy and commercial aircraft are noise sources . Airplanes, including army, naval and commercial aircraft, have become one of the most important environmental factors in terms of noise, and industry has identified much of their efforts and concerns. Noise abatement is the focus of modern research and development. Too much noise obviously damages our physical and mental health, so it makes sense to make a technical assessment of the noisy technology. Conflicts of interest in connection with aircraft noise are known. Propeller aircraft are the dominant noise. Many factors that contribute to the sound field in the propeller aircraft lead to extensive research to identify and improve the internal noise reduction techniques as noise sources .
2.5 Shipping noise
Anthropogenic noise is now considered a global problem, and recent research has shown that many animals have a multitude of negative effects. Marine underwater noise is increasingly considered an important and omnipresent pollutant that can affect marine ecosystems globally . Ships and sea vessels are the source of this noise. Noise exposure varies markedly between the sites according to the number of the ships and sea vessels . Due to the shipping noise, marine mammals and other marine life is vulnerable to be at risk as they require relatively quiet place to live but shipping noise could have substantial impacts on them and cause migration  (Figure 1).
3. Types of noise
Noise has different types according to the intensity, duration and frequency as continuous noise, intermittent noise, impulsive noise and low frequency noise.
3.1 Continuous noise
Continuous noise means the same noise frequency, intensity and quantity which is supplied to people and workers for longer periods of time like machinery operation in textile industry has the same amount, frequency and intensity for 6–8 hours of a working shift . It is the noise which affects the industrial workers health badly by causing headaches to high blood pressure and other heart problems .
3.2 Intermittent noise
Noise which can occur at regular or irregular intervals is intermittent. This type of noise includes all the traffic vehicles noise and community noise as these are not the regular and continuously produced and varies with source [62, 63, 64, 65].
3.3 Impulsive noise
This type of noise is produced instantly and reduced in the same way. Its types include ticking of clock, striking of hammer on something, water drops falling from height, and all the other noises in impulse forms. This type of noise also disturbs communication between people, induces stress, and anxiety in experimental population . Mitigation of impulsive noise is extensively studied in wireline, wireless radio, and powerline communication systems [3, 67, 68].
3.4 Low frequency noise
Low frequency noise is common with background noise in urban environments and comes from road vehicles, aircraft, industrial machinery, artillery and mining explosions, wind turbines, compressors and ventilation or air conditioning systems. The effects of low-frequency noise are worrying because they are universal (effective propagation) compared to many structures, and many structures (home, wall and hearing protection) are less effective at attenuating low-frequency noise than other sounds. Intense low-frequency sounds seem to produce obvious symptoms, including respiratory disorders and hearing pain. Although it is difficult to determine the effect of low-frequency noise for methodological reasons, there are indications that some of the adverse effects of noise are usually due to low-frequency noise: loudness ratings and disturbing responses are sometimes given for equal sound pressure levels. Low frequency noises are greater than other noises, hum or vibration caused by low frequency noise amplify problems, and speech intelligibility can be reduced by low frequency noise more than other sounds, except for noise in the frequency range of the speech itself due to the upward propagation of the masking [69, 70, 71, 72] (Table 1).
|No.||Category/Area||In 1st July 2010||From 1st July 2013|
|Limits in (dB)|
|Day time||Night time||Day time||Night time|
4. Health effects of noise
In light of the in-depth studies presented in Table 2, it can be concluded that traffic accounts for 80% of the environmental impact of noise . It is generally believed that deafness, high blood pressure, ischemic heart disease, discomfort and insomnia, as well as effects on the immune system, are the cause of the noise pollution. In addition to the above diseases, headaches, dizziness, sleeplessness, high blood pressure and hypertension are the common diseases caused by noise.
4.1 On humans
Traffic noise emissions consist of complex components, including horns, engine noise and tire friction. It is estimated that the noise pollution is affected by traffic noise , learning disabilities, loss of communication and lack of attention [75, 76]. Epidemiological studies have shown that traffic noise increases the frequency of arterial diseases, hypertension and strokes as well as vascular dysfunctions . Non-hearing effects such as activity, sleep and communication disorders can trigger a range of emotional reactions, including nuisance and subsequent stress, increased blood pressure and dyslipidemia, increased blood viscosity and blood sugar, and activation of the blood coagulation factor [78, 79]. Due to noise pollution, also higher memory disturbances and oxidative stress were observed .
4.1.1 On industrial workers
Occupational noise exposure to workers have adverse effects on workers’ health by increasing hypertension, sleep disturbance , cardiovascular diseases, blood pressure, hypertension [82, 83], exhaustion and overworking, mistakes performed in various operations due to noise disturbance , memory impairment , increased pulse rate , hearing loss and diabetes [87, 88].
4.1.2 On public
Technology, modernization and residential complexes usually occur near the population, so that the resulting increase in noise is recorded. The environmental impact of noise is closely related to health consequences, including discomfort, sleep disorders and cardiovascular disease [89, 90]. In addition, noise can seriously damage communication, memory function and hearing .
4.2 On animals
Noise levels are steadily increasing worldwide and may potentially affect many animal species. Short-term exposure can affect the behavior and physiology of birds, reproductive system as birds avoid reproduction in noisy places . Animals also suffer human like disabilities like hearing loss, loss in responsiveness, dizziness and disturbance . Traffic noise reduced foraging efficiency in most bats . Monkeys also live in noise free areas as exhibited by a study in which continuous noise was supplied in the habitat of the monkeys in Brazil, monkeys moved from that area to noise free area indicating that they also do not like noise . Noise effects on wildlife have also been widely studied and results indicated that they also prefer to live away from noise like bears, wolves, ants, lions and larger animals like elephants and whales  (Table 2).
|Sr. no.||Human health effects||Effects on animals|
|1||Headache||[97, 98]||Hearing loss|||
|2||Dizziness||||Increased heart rate|||
|3||Annoyance||||Increased risk of death|||
|4||High blood pressure||||Habitat loss|||
|5||Hypertension||||Trouble in finding prey|||
|6||Hearing loss||||Trouble in finding mates as in frogs|||
|7||Depression||||Impaired reproduction in marine mammals|||
|8||Sleeplessness||||Affects balance system of squid|||
|11||Difficulty in communication|||
5. Noise control and minimization
As it is widely discussed that noise has different negative effects on almost all the inhabitants of the planet, it is also one of the priorities that noise should be minimized to avoid the negative health impacts on the humans and animals. Due to its different sources, same technology cannot be used to address all types of noise. So, different technologies are adopted worldwide to overcome the noise impacts. Some of them are discussed below.
5.1 In industrial areas
The incorporation of sustainable industrial planning and development cannot be achieved without proper addressing of the noise pollution. Despite the proven impacts of noise pollution on the worker’s health, there remains a lack of systematic methods to reduce the impacts of noise within the industries [118, 119]. One of the major advances have been recently demonstrated for the long-term noise minimizing technology from the Department of Defense, Australia to reduce the workplace exposure from military and industrial noise sources . Application of personal protective equipment like ear plugs and ear mufflers are the general safety measures which are taken by the employer and workers themselves . Sealing of the machinery by using rubber is also used to minimize the vibrations and noise of the machinery in some industries . Glass industry is among the loudest noise producing industries and the workers in these industries are advised to use hearing protection equipment like ear plug or mufflers .
A recent technology called operating room technology is set up to address the occupational noise effects in which all the workers of the operating team are issued headsets with microphones. The headsets filter out background noise and the microphones enable interactive communication among and between .
5.2 In residential areas
Noise in residential areas is produced by traffic, celebration parties, loud music and playgrounds. Although the noise is a non-market good, the attempts of its evaluation have been increasing, usually by estimating the economic costs arising from exposure to noise, lost prices of property and medical expenses. It is estimated that plots located in the zone with noise exceedance the limits are 57% cheaper than those located in silent zone [125, 126]. The noise in the residential areas can be minimized by shifting to silent zones, using porous materials for house building or porous filters and planting hedges. In addition to this, some suggestion are also given by the authorities like exclusion of the traffic and train horn in or near residential areas, inclusion of noise barriers and removal of the railway tracks [127, 128, 129].
5.3 In commercial areas
There is an urgent need to reduce commercial noise being increased day by day due to increased commercial activities [130, 131]. Noise in these areas can be controlled or minimized by limiting transportation activities in markets in daytime, limiting commercial aircraft flights or changing the flight time to night .
5.4 In hospitals
Problems related to environmental noise are not confined outside the hospitals, but it became a major issue in the hospitals too. It needs to be solved because silence and peace in hospitals is a major contributor in healing of the patients . Noise pollution in the operating rooms is one of the remaining challenges. Both patients and physicians are exposed to different sound levels during the operative cases, many of which can last for hours. For noise monitoring and control, sound sensors can be installed in patient bed spaces, hallways, and common areas to measure the noise levels and its control accordingly [134, 135]. Reactive noise barriers can also be installed in hospital facilities . As we know that noise is produced from vibration, friction, collision and shocks, so by avoiding these phenomena’s, we can avoid noise by using rubber and proper lubrication in machinery .
5.5 In educational institutions
The learning environment dramatically affects the learning outcomes of students. Noise is a major factor which can distract students , induce attention loss and concentration difficulties, anxiety and headache . To address these problem in educational institutions, traffic noise should be regulated, and traffic can be banned accordingly if found exceeding. School and college bus-stands should be away from the school and colleges. Educational institutions should not be established near the railway tracks, stations and airports [140, 141, 142].
6. Conclusion and recommendations
There is a little difference between noise and a sound. A sound can be a noise when it is loud and intensive. Categorization of a sound and noise is also depending upon the choice of the listener and the circumstances. For example, rock music can be pleasurable sound to one person and could be an annoying noise to another person. Likewise, dog’s barking is not a noise, but when it becomes continuous and disturbs people, it can be regarded as noise.
Noise has different sources and it can cause hearing loss, dizziness, heat diseases, headaches, high blood pressure, hypertension and nausea based upon the its intensity. To control environmental noise, different techniques and equipment are used according to the situation and requirement. In industries, ear plugs, and mufflers are used, rubber sealing and noise sensors are used in hospitals and shelter belts are used in residential areas for protection against adverse effects of noise. For future, it is necessary to work on reducing the vehicular sources of environmental noise by developing low noise producing automobile vehicles, aircrafts and ships.
The authors are highly acknowledged to Mr. Junaid Latif and Mr. Waqas Mohy Ud Din for their precious time given to review this manuscript.
Conflict of interest
The authors declared no conflict of interest for this chapter’s publishing.