Even as recently as the mid-19th century, most of the sounds on planet Earth were mostly of a natural origin. In a matter of just over three quarters of a century, most of the sounds on the planet are now being caused by man’s technological inventions which not only disrupt the natural environment but also have a direct and deleterious effect on the health of the human and animal population of this planet. However, as technological progression seems inevitable, noise is becoming an integral component of present-day life, especially in urban areas as compared to the rural. Realizing the fact that noise pollution is becoming a matter of great concern the World Health Organization (WHO) has declared noise as the second largest environmental cause of health problems, just after the impact of air pollution.
This chapter attempts to provide a broad view on the definition of the term ‘noise pollution’, its effect on health and the legal options available in our country to ensure that noise in our environment is kept within acceptable limits. It also includes details of how individual citizens can play a part in this endeavour.
Learning Objectives
• Recognizing noise as one of the causes of pollution
• Understanding measurement of noise and its value in determining noise pollution
• Sources of noise pollution
• Ways and means of combating noise pollution (noise control)
• Legal options available in India for noise control
• Ways to become a responsible citizen and contribute towards noise control in an individual capacity
The word ‘noise’ is derived from a Latin word ‘nausea’, meaning a condition wherein one feels like vomiting. According to WHO’s findings, noise is the second largest environmental cause of health problems, just after the impact of air pollution and that “noise must be recognized as a major threat to human wellbeing”. In common man’s language noise refers to unwanted sound and, in fact, noise pollution is a type of energy pollution in which distracting, irritating or damaging sounds are freely audible. Normal sound becomes undesirable when it disturbs our normal activities such as working, sleeping and conversations.
In 2018 (the latest year for which data is available) Chennai was ranked as the noisiest among India’s six metros with average noise levels during the day being 67.8 dB.1 The Government of India mandates that noise levels in residential areas should not exceed 55 dB during the day and 45 dB at night. In the 13 monitoring stations in residential areas across the six cities, this limit was violated during both day and night throughout 2018. Even designated silent zone areas around hospitals, for instance, do not meet noise pollution standards; the area around Paradise Junction in Hyderabad, a major commercial hub and traffic choke point, is India’s loudest at 79 dB.
As with other forms of energy pollution (e.g., heat and light), noise pollution contaminants are not physical particles, but rather waves that interfere with naturally occurring waves of a similar type in the same environment.
Sound has both volume and pitch, and is measured in terms of its intensity or loudness (often referred to as volume) in units called decibels (dB). The unit is named in honour of Alexander Graham Bell, the inventor of the telephone and audiometer. Pitch is the number of times per second that a sound pressure wave repeats itself. The unit of frequency is called Hertz (Hz). It is named after Heinrich Rudolf Hertz, a German physicist.
Humans with normal hearing can hear sounds between 20 Hz and 20,000 Hz. Frequencies above 20,000 Hz are known as ultrasound. The quietest noises the human ear can perceive are around 10 dB, whereas sounds of 130 dB are considered painful. Sound travels at a speed of 343 metres per second in air and 1484 metres per second in water. Table 13.1 provides a list of activities and the corresponding noise levels.
Noise pollution could be caused by the following.
1. Road Traffic Noise
• Traffic noise has increased in recent years with an increase in the number of vehicles.
• Narrow streets and tall buildings augment traffic noise through reverberation of sound waves.
• Low-flying aircraft including military aircraft add a new dimension to community discontent.
• As a result of aircraft noise 12,500 school children suffer from reading impairment, according to Environmental Noise in Europe – 2020, No. 22/2019.
3. Noise from construction and civil engineering sources include pneumatic hammers, air compressors, bulldozers, loaders, dump trucks and pavement breakers.
4. Noise from industries
Neighbours of noisy manufacturing plants can be disturbed by sound they create. Interior noise sources have a significant impact on industrial workers among whom noise-induced hearing loss is unfortunately common. Humans also damage their ears if they are exposed to noises that are less loud, but that are heard more often. For example, office workers who endure noise from telephones and loud machines daily may suffer some hearing loss over time. Workers in loud factories also experience hearing loss.
5. Noise in buildings
• When apartments are poorly designed and constructed, internal building noise from plumbing, boilers, generators, air conditioners and so on can be audible and annoying to the occupants.
• Improperly insulated walls and ceilings can transmit sound of amplified music, voices, footfalls and noisy activities from neighbouring units.
• Events, weddings, public gatherings, use of loudspeakers and so on
• Neighbourhood noise – gadgets, household utensils, musical instruments, transistors and so on
• Unnecessary usage of horns
Playing loud music on a personal stereo can also damage hearing. Noise hurts more than just hearing. When people are exposed to loud noise, their bodies react as if in danger resulting in increased heart rate, stress, eye conditions, muscle tension, elevated cholesterol levels and hormone secretion, high blood pressure, and migraines. Noise also impairs concentration; studies have shown that children’s learning and achievement can be affected.
Long-term exposure to noise affects the health of an individual in a variety of ways.
• Hearing loss
• Sleep disturbance
• Negative effects on cardiovascular and metabolic systems
• Cognitive impairment in children
• High blood pressure
• Stress
According to the European Environment Agency report Environmental Noise in Europe – 2020, 20 per cent of Europe’s population is exposed to long-term noise levels which have harmful effects on their health. Environmental noise pollution contributes to 48,000 new cases of ischemic heart disease every year as well as 12,000 premature deaths; 22 million suffer from chronic high annoyance and 6.5 million suffer from chronic high sleep disturbance.
According to WHO, South Asia already has the highest prevalence of hearing loss in the world among children and the elderly.
Noise pollution can also affect the economy of a country. Properties located in noisy areas are sold and rented at lower prices.
Certain sectors can become less attractive (as very few sectors can operate in noisy surroundings there would be few takers) and productivity may decrease due to the effects of noise on health.
Noise at night affects the quality of sleep, which is an important determinant of well-being and productivity. Even during day time, working in a noisy environment affects productivity. An experiment in Kenya found that a 10 dB increase in noise reduces productivity by around 5 per cent. 3
Noise control, also known as noise mitigation, comprises a set of actions aimed at reducing noise pollution or reducing the impact of noise, outdoors or indoors.
Noise control measures and effective social awareness programmes should be implemented at personal, industrial and community levels to highlight the ill effects of noise pollution on the health of individuals and the urgent need to ensure that noise pollution does not become a menace.
The Central Pollution Control Board under the Ministry of Environment and Forest, Government of India, recommends noise control measures to be deployed as appropriately applicable at the source of noise, along the path of the noise and at the receiving end in accordance with R. A. Bolt and K. U. Ingard’s source path receiver model.4
1. Reduction of the exciting forces, for example, noise reduction of impacts or impulsive forces, balancing of moving masses, reduction of frictional forces by proper alignment and lubrication, and so on
2. Reduction of the response of various components of the system to these exciting forces, for example, by application of vibration-damping materials to the radiating surfaces
3. Changes in operating procedure, for example, a factory adjacent to residential areas should suspend or reduce noise-generating operations at night
4. Maintenance of automobiles
5. Prohibition on the use of loudspeakers
6. Speaking in a low voice
7. Selection and maintenance of machinery
8. Control of vibrations
Controlling the transmission path of noise so as to reduce the energy that is communicated to the receiver can be achieved in a number of ways.
1. Increasing the distance between the source and the receiver
2. Path deflection using barriers
3. Properly designed enclosures
4. Providing sound-absorbing material in a room where both the source and the receiver are present. Most of the reflected sound can be avoided.
5. Constructing buildings with suitable noise-absorbing materials for the walls, windows, doors and ceilings
6. Planting of bushes and trees along the roads to help in controlling noise pollution by absorbing high frequency sound waves
1. Use of personal protective equipment, for example, ear plugs, ear muffs, noise helmets and so on
2. Educating the public, for example, creating public awareness regarding noise pollution
3. Exposure control, for example, rotation of personnel so that work assignments in the noise-intense area are for a limited period only
4. Factories and industries to be located far from residential areas
Apart from the Indian Penal Code (detailed in chapter F – Regulations and Implementations), other laws pertaining to noise control in India include the following.
1. Criminal Procedure Code
Under Section 133 of the Criminal Procedure Code, whenever a District Magistrate or a Sub Divisional Magistrate or any other Executive Magistrate specially empowered in this by the state government on receiving the report of a police officer or other information and on taking such evidence (if any) as he thinks fit has the power to make a conditional order requiring the person causing nuisance to remove such nuisance.
2. Factories Act, 1948
The Factories Act does not contain any specific provision for noise pollution control. However, the third schedule under Sections 89 and 90 of the Act mentions ‘noise induced hearing loss’ as a notifiable disease. Under Section 89 of the Act any medical practitioner who detects any notifiable disease including noise-induced hearing loss in a worker has to report the case to the Chief Inspector of Factories along with all other relevant information. Failure to do so is a punishable offence.
3. Motor Vehicles Act, 1988, and Rules Framed Thereunder
Sections 119 and 120 of the Central Motor Vehicle Rules, 1989, deals with reduction of noise.
• Every motor vehicle shall be fitted with an electric horn or other device approved by the Bureau of Indian Standards and the registering authority for use by the driver of the vehicle and should be capable of giving audible and sufficient warning of the approach or position of the vehicle.
• Every motor vehicle shall be so constructed and maintained to confirm to the noise standards as approved by the Bureau of Indian Standards from time to time.
• Section 120 silencers.
• Every motor vehicle shall be fitted with a device (hereinafter referred to as silencer) which by means of an expansion chamber or otherwise reduces as far as practicable the noise that would otherwise be made by the escape of its exhaust gases from the engine.
• Every motor vehicle shall be so constructed and maintained so as to conform to noise standards as indicated in Table 13.2 and these standards shall be tested as per Indian Standards IS 3028.
4. Law of Torts
Under the law of torts, a civil suit can be filed claiming damages for nuisance. Nuisance as a tort means an unlawful interference with a person’s use or enjoyment of land or some right over or in connection with it.
5. The Air (Prevention and Control of Pollution) Act, 1981
Noise was included in the definition of air pollution in the Air (Prevention and Control of Pollution) Act by an amendment in 1987. Obviously, all the provisions of the Air Act become automatically applicable in respect of noise pollution also. Ambient noise standards have been notified under the Air Act, 1981.
6. The Environment (Protection) Act, 1986
The Ministry of Environment and Forest notification on Noise Pollution (Regulation and Control) Rules, 2000 (Annexure 1), covers various aspects of noise pollution. Earlier noise standards for various sources were notified under the Environment (Protection) Act, 1986.
7. Regulations on loudspeakers / public address systems
Many states have their own regulations on loudspeakers / public address systems.
a. The Union Territory of Delhi Loudspeakers (Licensing and Controlling) Regulations, 1980
b. The Orissa Firework and Loudspeakers (Regulation) Act, 1958
c. Madhya Pradesh (Control of Music and Noise) Act, 1951
The Central Pollution Control Board tracks noise level through monitoring stations spread across India’s major cities.
Some of the other measures that could be adopted towards ensuring noise reduction in metros could include the following.
1. Road noise
• Use of noise barriers
• Newer roadway surface technology
• Traffic control
• Limiting time for heavy duty vehicles
2. Providing quiet tyres for public transport
3. Promoting electric buses and cars
4. Promoting active travel walking or cycling
5. Designating quiet areas with strict adherence to maintaining low noise levels
6. Better urban and infrastructure planning
7. Changes in people’s behaviour
1. What is meant by ‘Day time’ and ‘Night time’ under Noise Pollution (Regulation and Control) Rules, 2000?
a. Day time shall mean from 6.00 a.m. to 10.00 p.m.
b. Night time shall mean from 10.00 p.m. to 6.00 a.m.
2. What is the silence zone?
A silence zone is an area comprising not less than 100 metres around hospitals, educational institutions, courts, religious places or any other area which is declared as such by the competent authority.
3. How many decibels can the human ear handle?
Immediate and irreversible nerve damage can be caused by sounds at 140 dB or higher (120 dB in young children). However, damage also occurs at lower sound levels, and this harm accumulates over time. Any sound above 85 dB can cause wear and tear of your ears which reduces your hearing acuity over time.
4. What are the restrictions on using loudspeakers or musical systems at night?
5. What is the noise level for using loudspeakers or public address systems?
Any person using loudspeakers or a public address system shall maintain the noise level and restrain it from exceeding 10 dB (A) above the ambient noise standards for the area specified or 75 dB (A), whichever is lower.
6. What is the noise level for a private sound system?
A person owning a private sound system or a sound-producing instrument shall not let the noise exceed 5 dB (A) above the noise standards specified for the area in which it is used.
7. What are the restrictions on bursting firecrackers?
A person shall not burst sound-emitting fire crackers in silence zones or during night time.
8. What are the restrictions on noise-making construction equipment at night near residential areas?
A person is restricted from using sound-emitting construction equipment during night time in residential areas and silence zones.
9. What are the prohibitions on violating the silence zones?
A person shall not undertake the following acts in silence zones.
• Play any music or use any sound amplifiers
• Play a drum or tom-tom or blow a horn, either musical or pressure, or trumpet or beat or play any instrument
• Conduct any musical or other performance to attract a crowd
• Burst sound-emitting firecrackers
• Use a loudspeaker or a public address system
10. What is the restriction on using horns in silence zones?
11. What are the consequences of any violation in the silence zones?
a. Anyone who contravenes the provisions of the Noise Pollution (Regulation and Control) Rules, 2000, shall be punished with imprisonment for a term which may extend to five years or with fine which may extend to one lakh rupees, or with both, and in case the failure or contravention continues, an additional fine which may extend to five thousand rupees for every day during which contravention continues.
b. If the person continues contravention beyond a period of one year after the date of conviction, the offender shall be punishable with imprisonment for a term which may extend to seven years.
1) In Japan, the Yokohama Tyre Company has introduced a new high-performance tyre that gives a quiet ride.
2) Korean engineers have developed an anti-noise system for computers that reduces a typical noise level of 30 dB to a nearly undetectable 20 dB.
3) Researchers in the United States have invented a new composite consisting of alternating layers of sound-absorbing foam and sound-containing vinyl that can be placed in machinery housings to reduce noise.
4) At the Georgia Institute of Technology an inventor has developed a quiet curtain for nursing home patients who cannot sleep that is made of noise-absorbing materials that can reduce noise by 12 dB.
5) In Germany roads are paved with materials that reduce sound, and tyres are manufactured to whine less. Also, lawnmowers and other equipment are designed to operate quietly.
In order to counter the impact of increasing amount of noise (which seems inevitable) some companies are developing a new technology called anti-noise. This technology is based on creating a sound that exactly matches the noise. When the sound waves from the anti-noise device meet the sound waves from the noise-causing device they cancel each other out. In other words, humans do not hear any noise.
Even if we cannot eliminate noise pollution, it may be possible to use anti-noise devices to escape some of the damage that can be caused by noise.
Consequent to WHO categorizing noise as the second-largest environmental cause of health problem, noise pollution and the need to ensure that the noise level is kept within allowable limits as per the location is gaining importance globally. Though scientific innovation contributes towards noise generation on the one hand, on the other hand it simultaneously finds innovative ways and means of reducing noise levels.
As far as India is concerned noise pollution across metros is a reality that needs to be addressed on an urgent basis to ensure the well-being of our citizens, especially children and the elderly. Noise problems cannot be properly evaluated and addressed without producing noise maps of our cities and drawing up action plans accordingly. It is interesting to note that the Mumbai police have launched a novel ‘Honk More, Wait More’ scheme at traffic junctions. If any impatient driver honks at signals, waiting time is prolonged.
• Noise pollution in Indian metros is indeed a major concern
• Urgent steps are to be taken by the Ministry of Environment, Government of India, to reduce noise pollution to safeguard the health of the citizens of our country, especially children.
• Noise mapping of areas where noise pollution is beyond acceptable limits.
• Strict enforcement of law and increase in fine for violation
• Improving the civic sense of the population and motivating them to respect law in their own interest and in the interest of others.
It is only through a combination of different measures, evolved to suit our culture and environment, along with the application of technological improvements and ensuring strict adherence to the law, that we can save ourselves from noise pollution and help towards building a healthy nation.
The human ear has an extraordinary capacity to receive and perceive any type of signal, sound or noise present in the environment. Noise is usually defined as any unwanted or undesirable sound. Nowadays noise is present all over the world.
Learning Objectives
• To know the different types of noises and permissible noise levels in the environment
• To identify and measure the different sources of noise in industry (organized sector)
• To get familiar with the Hearing Conservation Education Program (HCEP)
There are a variety of sounds all around us. Outdoor noise sources include vehicles, domestic buildings, machinery from industries, construction sites, commercial buildings, public places, and public address systems. Indoor noise sources include banging of doors; moving of furniture; television; household gadgets such as pressure cookers, vacuum cleaners, washing machines, sewing machines, mixer grinders and air conditioners; and office equipment. These noises can range from 40 dB (A) to 120 dB (A). Though the range of the noise sources is high, not all sounds from these sources are hazardous to the ear. The World Health Organization (WHO) defines noise pollution as sounds or noises that are above 65 dB.[ 1] Sound or noise becomes hazardous when it exceeds 75 dB and excruciating above 120 dB.[ 2, 3] Hence, it is advisable that the noise level be lower than 65 dB during the daytime and not more than 30 dB of ambient noise at night. The Central Pollution Control Board (CPCB) has stipulated the permitted noise levels for different areas in India. The permissible limit in industrial areas is 75 dB for daytime and 70 dB at night. In commercial areas, it is 65 dB and 55 dB, while in residential areas it is 55 dB and 45 dB during daytime and night-time, respectively.[ 4] State governments have declared ‘silent zones’ which include areas that lie within 100 meters of the premises of schools, colleges, hospitals, and courts. The permissible noise limit in this zone is 50 dB during daytime and 40 dB at night. Noise pollution and its sources are addressed by the Noise Pollution (Regulation and Control) Rules, 2000. The standards for noise emitted by motor vehicles, air conditioners, refrigerators, diesel generators, and certain types of construction equipment are prescribed in the Environment (Protection) Rules, 1986. Noise emanating from industries is regulated by the State Pollution Control Boards (SPCBs) / Pollution Control Committees (PCCs) for States / Union Territories under the Air (Prevention and Control of Pollution) Act, 1981.[ 5]
‘Building machines to build the product’ occupies the key position in the country’s industrial development. India is one of the foremost exporters of industrial machinery required for steel, mining, fertilizer, cement, petrochemical, and heavy engineering. However, the production and use of these machines can cause serious health problems, including hearing loss.
Different types of machinery produce different noises. The sound pressure level of the noise varies depending on the usage of single or multiple machines in the factories. It also depends on the sort of noise source, distance from the source to the ear, and the kind of employee work atmosphere.[ 7] The various sources and their sound pressure includes compressors emitting greater than 105 dB (A), large electric motors 106 dB (A), woodworking machines 106 (A), pneumatic tools 110 dB (A), electric hammers 88 to 103 dB (A), and planing wood machines 96 dB (A) to 101 dB (A). For effective occupational hygiene practice, the noise emitted from the source needs to be measured using a sound level meter. The noise source measurement needs to have a detailed narrow-band frequency analysis to determine the specific frequency component of the sound, root mean square (RMS) detection of the sound, wide range of amplitude of the intensity of the sound, record the characteristic of the short as well intermittent noises and also the reverberation and vibration if any. However, the maximum permissible sound level recommended by the National Institute of Occupational Safety and Health (NIOSH, 1998)[ 8] is 85 dB (A) for 8 hours per day using a 3 dB exchange rate at the worker’s ears. The maximum permissible level depends not just on the intensity of the sound source but also on parameters such as frequency, duration, and the spectrum of the sound. When these parameters are above the permissible limit, noise can cause severe damage to the ears. It can also cause other physical and psychological problems.[ 9] A noise dosimeter can be used when the noise is impulsive, intermittent, and variable to determine the average exposure of a worker’s ears to noise. The optimal position of the microphone of the noise dosimeter is the mid-top of the shoulder near the ear more exposed to the noise.[ 10]
A noise survey may be required to identify the noisy areas in various industries. Such a survey can measure noise levels at selected locations or sections where the noise is generated. Surveying of noise includes sketching a map of the location of the workers and of the machines emitting noise.
The noise survey points of the source of sound and the worker.
Hence, based on the noise survey reports, if a worker is going to be exposed to more than the permissible limit of noise according to the noise regulations, the hearing conservation education program (HCEP) needs to be implemented.
The HCEP requires employers to monitor noise exposure levels in a way that accurately identifies employees exposed to noise at or above 85 dB averaged over eight working hours, or an 8-hour time-weighted average (TWA). The HCEP includes:
• Annual and periodic monitoring of noise exposure
• Noise control measures
• Hearing protection devices – selection, use, and maintenance
• Periodic audiometric testing
• Education, motivation, and training
• Record keeping
When there is an indication that any employee in an organized sector is exposed to a noise level of 85 dB (A) for 8 hours, the employer of the organization has to notify the Health and Safety Officer of the sector to initiate and execute a noise monitoring program. As a part of the program, a noise survey is undertaken using a sound level meter and a noise dosimeter evaluates personal exposures. Monitoring the noise level exposure has to be repeated periodically. The noise pressure levels are measured whenever there is any change in the manufacturing process, equipment, maintenance of the equipment, or if the ear protectors being used by employees are not suitable.
Noise control measures are a systematic process. The hierarchy of noise control procedures needs to be followed by the occupational safety and health professionals in the employment sector to implement a viable and effective control of the noise. The program involves engineering and administrative control measures. The preeminent method to reduce noise is to block the delinquent at the source.
These measures include maintenance, modifying equipment, substitution of equipment, and isolation. The best-preferred approach is to remove the hazard by eliminating the equipment, device, procedure, machine, or material that is the source of generation of the noise, or installing ‘silencers’ (mufflers and baffles) on equipment. Suppose exclusion is not practical, substitute, or supplant unique equipment, substance, or process with another. Hazards can sometimes be ‘engineered out’ by redesigning the worksite, workstations, processes, and occupations. Hazards can also be isolated through restraint or enclosure or automated or mechanized. There is also a nationwide ‘Buy Quiet’ drive to get corporations and the military to buy noiseless machinery and specify the acceptable sound output in the order process during procurement. The ‘Buy Quiet’ approach requires employers of the sector and engineers to obtain noise production statistics or information before procuring the quietest available and affordable equipment. Though quieter equipment compromises the price, its high efficiency makes it worthwhile. Choosing soundless or noiseless equipment, systems, tools, and so on in the initial stages of procurement is the preeminent way to reduce noise at source. The second option would be reducing the noise in the path between the noise source and the receiver. This would generally involve adding barriers or obstacles, enfolding the equipment in sound-absorbing materials. The best engineering control measure to protect hearing is by constructing an acoustic barrier wall that can dampen sound from nearby machinery. However, this provides only a little reduction in the noise. If engineering controls cannot eradicate or control noise exposure, administrative controls can be used.
These controls do not remove the hazard as do engineering control measures. Some of the administrative control measures can include harmless work practices, rotation of employees’ work, restraining the period of certain operations of machinery, or hampering areas or work processes, work/rest rosters to reduce worker exposure to hazardous substances or conditions, limiting hours of work, replanning hazardous work during times when exposure, wet methods as opposed to dry sanding or sweeping. If the sector cannot incorporate a silencer (noiseless equipment) or acoustic barrier, or incorporate other engineering controls due to lack of practicality, or if the worker cannot be steered away from the noise source completely, the last way to dampen noise is by stopping the noise with hearing protection devices (HPDs) for the receiver.
The selection of hearing protection need will depend on the characteristics and features of the noise source, employee preference, and attenuation required. Different types of HPDs are available, including earplugs, semi-inserts, earmuffs, and helmet with earmuffs. The different earplugs include pre-molded earplugs, custom earplugs, disposable plugs with cushions, shooters’ earplugs, reusable plugs, sound-isolating earplugs, musicians’ earplugs, and filter earplugs. These earplugs have attenuation levels ranging from 10 dB to 40 dB. There is high variability in the attenuation provided by these ear protective devices across frequencies. Hence, the selection of HPDs is a huge challenge. However, double / dual hearing protection using custom-made communication earplugs worn under a headset or a helmet appears to be the best. Unlike other HPDs, this combination does not interfere with speech intelligibility. Overall, HPDs do not eradicate all sound, which would be unrealistic and possibly dangerous. However, if appropriately used, they reduce noise to harmless and safer levels at ear level. Thus, HPDs features at the bottom of the pyramid of noise control approaches and should not be relied upon as the crucial means of noise control. Rather, they should be treated as the last alternative for monitoring noise exposure—only to be used as a temporary or supplementary measure where other measures higher up the hierarchy of noise control strategies are pending application or where they have been attempted and proven insufficient, unsuccessful, or impossible.
Different types of hearing protective devices.
A very important aspect of the HCP is audiometric testing. It is mandated that an audiologist perform audiometric testing to determine if a worker is losing his hearing or if such a loss has been prevented. A baseline audiogram (14 hours after exposure to noise during work) is obtained for all the employees within six months. The audiograms are compared against subsequent audiograms and assessed each year. If any changes in the thresholds of greater than 10 dB (standard threshold shift) are noticed, appropriate noise control measures must be implemented immediately.
The effectiveness of the HPDs depends only if the employee wears it correctly and uses it when necessary. However, the education regarding the same is less know. This is true of HCEPs in general. Hence, an annual training program must be provided to each employee included in the HCEP. Both employers and workers must be educated about the importance of good hearing and avoiding hearing loss due to noise exposure. The training program includes maintaining noise control; effects of noise on hearing and other aspects; the purpose of hearing protectors; selection, fitting, use, and care of ear protective devices; and the purpose of audiometric testing. Providing workers with this input increases their involvement with the program and enhances the likelihood of securing their participation
The employer is responsible for maintaining the documents and records related to hearing tests, noisy surveys, employee exposure measurements, noise control measures, and use of appropriate ear protective devices. The employer must also frequently evaluate and maintain records on the HCEP along with appropriate supporting documents.
Understanding the importance of implementing effective health and safety methods provides an opportunity for intervention and the potential for reducing the number of occupational medical conditions. The HCEP is viable. However, to work, it must be vigorously supported by the management and couched in a holistic framework that includes enforcement, education, motivation, and the availability of comfortable, effective HPDs. To conclude, hearing loss due to noise exposure is painless, permanent, and progressive, but it is highly preventable. Hence, a Hearing Conservation Program can be established as a national program.
This chapter focuses on preventing the harmful effects of noise on health in individuals working in the unorganized industrial sector. Implementing a hearing conservation program (HCP) in these categories of workers is an enormous challenge as monitoring the HCP is going to be more tedious and less effective as opposed to implementation in the organized industrial sector. How hearing loss due to hazardous noise can be prevented in construction workers, laborers employed in the small-scale industry, handloom or power loom workers are discussed in this chapter. After understanding the contents of this chapter, the readers should be able to plan effective options to prevent the development of noise-induced hearing loss (NIHL) in industrial workers in the unorganized sector.
Learning Objectives
• To understand the scenario of developing occupational hearing loss in the unorganized industrial sector.
• To understand how hearing loss due to hazardous noise can be prevented in construction workers, laborers employed in the small-scale industry, handloom or power loom workers, etc.
• To be able to plan effective options to prevent the development of NIHL in industrial workers in the unorganized sector.
Individuals working in the unorganized industrial sector/informal sector often face challenges in multiple forms. This sector is not as well-structured as the organized one. The unorganized sector is not strictly bound by rules as it is primarily not overseen by the government. The employees are often not given the benefits and privileges; unlike what they receive in the formal sector. Hearing loss is one common concern in individuals working in the industrial sector. The problem is much more prominent as there is a lack of proper governance in the informal industrial sector. Hearing loss in the industrial sector is usually the end result of exposure to continuous or intermittent noise at work. The workers are often exposed to hazardous noise levels and are not aware or informed of the ill-effects of loud noise exposure. Usually, the risk is higher in the unorganized sector due to their long and unmonitored work schedules. The workers’ categories include laborers of small-scale industry, construction workers, power loom workers, workers in tanneries, some workers in the shopping complex, etc.
The industries that contribute to noise at the workplace in the unorganized sector, including printing, sawmill, textile, and mining1, are at risk of developing hearing loss due to noise exposure. The more the duration of noise exposure, the higher the risk of developing hearing-related problems2. Noise induced hearing loss is found to be the second most common form of the sensorineural type of hearing loss after presbycusis3. The hearing loss is often sensorineural in nature, wherein the damage occurs in the inner ear. Some individuals even experience acoustic blast injuries. The causative factor for the development of hearing loss is primarily lack of awareness about the hazardous effects of noise exposure. Exposure to noise leads to the death of sensory cells in the cochlea, along with causing damage to the vestibulo-cochlear nerve fibers. The sensory cells gradually die off due to apoptosis (dissolution of cochlear hair cells) or necrosis (rupture of the cochlear hair cells), when exposed to prolonged or high levels of noise4. Hearing loss due to noise exposure is often accompanied by tinnitus perception. Tinnitus is the perception of ringing or buzzing sound in the ear, in most cases due to some amount of cellular loss of the inner ear. Tinnitus is considered to be one of the classical clinical presentation after getting exposed to loud noises, typically due to cell injury or damage to the nerves associated with hearing. The degree of hearing loss can vary from minimal to moderately severe, and most of them do not show hearing loss beyond moderate degree. A classical 4 kHz notch5 (Boiler’s notch) in the audiogram is seen in most cases, especially in the initial stages of noise-induced hearing loss development. Gradually the loss extends to other neighboring frequencies as well; however maximum threshold shift in the audiogram is centered around 3 kHz to 6 kHz region.
Hearing conservation focuses on preventing the incidence of hearing loss or preventing the progression of loss in case the hearing loss has already occurred and in providing workers with the knowledge of protective devices to safeguard their hearing. Hearing conservation as a means to avoid the harmful effects of noise is challenging as the unorganized industrial sector is profit-oriented and not well-governed by government policies. However, the detrimental effects of noise on health need to be prevented as having hearing loss has a damaging effect on the quality of life. Hearing conservation in such a group of workers is planned with the notion that continued exposure to large noise levels over time causes permanent damage to hearing-related structures in the inner ear and the auditory nerve. Workers exposed to high levels of noise may be at risk of other harmful health effects as well.
The hearing conservation program should have the following steps for effective planning and administration. The measures should include:
a) Noise Surveys/Monitoring
b) Audiometric Testing
c) Hearing Protection Devices
d) Employee Education and Training and
e) Record Keeping.
Surveying the noise in the environment of concern/interest serves as the primary step in the hearing conservation protocol. The amount of noise prevalent in the workplace needs to be identified to know whether it is in the harmful range to cause noise-induced hearing loss. Mapping noise in the workplace serves as an ideal means to label or designate the work areas as hazardous zones if the amount of noise exceeds 85 dBA. These measurements are to be done using a well-calibrated sound level meter (SLM) set in the fast mode and A weighing network. The SLM microphone should be protected using a windshield and a distance of 1 or 1.5 m has to be maintained from the primary source of noise under consideration. Noise mapping will give accurate information about the amount of noise in the area under review. It will help in deciding whether there is a need for the workers to enroll in a hearing conservation program. The following noise measurements could be computed, namely LAeq (level equivalent), LAFmax, LAFmin, and exceedance level (at L90) for the measurements while doing noise mapping. LAeq provides information on the average noise level over a measured period (to be defined while doing the measurement, ideally done for the entire working duration, typically 8 hours). The value at L90 indicates that the noise levels are higher than the obtained L90 value for 90% of the time (e.g. beyond 85 dB); LAFmin and LAFmax gives information about the minimum and maximum noise levels recorded during the measurement period. By determining these characteristics of the measured noise, a clear idea about the noise levels at the place of work in the unorganized sector is made available, which enables the competent authorities to decide on further strategies for hearing conservation programs. The suitability of land use (location of the place) for a specific purpose compared to prescribed standards given by the noise pollution (regulation and control) rules (2000)6 can also be done based on the results of noise mapping. The areas can be classified into respective categories (Residential, Commercial, Industrial, Sensitive, and Mixed commercial residential) based on the noise measured.
In industries like handloom, specific noise measurements enabling labelling noise levels in each target area within the workspace need to be done to get a clearer picture of the hazardous noise levels. The noise levels need to be measured for shedding, picking, beating up and taking up stages, and the average noise levels (LAeq) during the job needs to be calculated to know the noise levels to which the worker is exposed. If the noise levels exceed 85 dBA, it is essential to include those workers in the hearing conservation program. One other way of measuring the amount of noise exposure of an employee is by using the noise dose meter. The amount of daily dose of noise exposure at the end of 8-hours-work shift, provides the best understanding about an employee’s noise exposure. A reading of 100 dose indicates that the employee is at risk of developing noise induced hearing loss. The value of 100 dose indicates that the employee is exposed to a minimum intensity of 90 dB for a period of 8 hours. Those workers need to be equipped with adequate hearing protective device during work to prevent development and/or progression of hearing loss. Survey/mapping results indicate whether engineering controls (e.g. greasing of equipment ball bearing, repair or replacement of spares that would help in noise reduction) or administrative controls (scheduling break time to increase the effective quiet periods) or a combination (both engineering and administrative controls) can help these workers safeguard their ears from developing hearing loss. Previous research carried out in India indicates the noise exposure in workplace to be 80.44 dB in bus drivers and 77.82 dB SPL in auto-rickshaw drivers; in traffic police it is 75.33 dB SPL, and in street vendors it accounted to 74.42 dB SPL7. Talukdar (2001)8 reported noise levels of 94 to 99 dB in the loom shed in a textile industry, which is high enough to cause significant hearing loss. As per the Damage Risk Criterion (DRC), exposure beyond 85 dB can cause considerable hearing loss if exposed for longer durations.
Noise level exposure can be considerably high in fabrication workers and other construction workers. A hand drill can generate noise levels beyond 90 dB and cause considerable temporary threshold shift (TTS) in hearing. If the exposure continues, even though intermittent, it can lead to a significant permanent threshold shift (PTS) in those workers who are exposed to noise. Identifying these individuals is quite a challenge as there is no clear evidence of short duration (other than loud impulse noises) noise exposure causing hearing loss when exposed over larger intervals. In such cases, it is always advisable to provide hearing protectors to the workers even when they are not exposed to noise, as detailed in the DRC. Intermittent noise exposures can also lead to hearing loss in the longer run.
Regular audiometric evaluation for those workers who are exposed to occupational noise in the unorganized industrial sector is also recommended. Suppose an individual is finding it difficult to follow conversation at a distance of one meter in the presence of noise at the place of work, this gives a clear indication that the amount of noise in the vicinity is beyond 80 dB SPL. An assessment of hearing is recommended for such individuals who are working in such noisy areas. Three forms of audiogram are recommended for industrial workers: pre-placement audiogram, monitoring audiogram, and terminal audiogram. The pre-placement audiogram is recommended for all the workers who are appointed to work in noisy areas. This needs to be done by a qualified Audiologist using a calibrated audiometer in a properly sound-treated room/booth before the individual starts working in the sector (ideally) or at least within six months of appointment. This serves as the baseline audiogram, and the record is to be preserved. A proper baseline audiogram record will also help to avoid unnecessary compensatory claims in the future. The second type of audiogram is called the monitoring audiogram. The monitoring audiogram is to be administered annually to see any standard threshold shift (STS). A STS is the hearing threshold shift from baseline. According to OSHA9, an individual is reported to have an STS once there is a threshold shift of 10 decibels (dB) or more at 2000, 3000, and 4000 hertz (Hz) in one or both ears and record of it needs to be maintained. Monitoring audiograms will help the audiologists to know whether the ears are getting affected due to noise exposure. If there is a shift in hearing threshold observed, hearing protection is recommended, if not used already. Additionally, a measurement of noise where the person is working is to be done. This will further clarify whether engineering or administrative controls are required to preserve hearing further. This is one of the most recommended ways to control the deleterious effects of noise on workers—frequent monitoring and providing feedback. A structured plan on when the hearing assessment is to be scheduled needs to be chalked out in any work industry where noise is present. Following these schedules and getting a hearing evaluation done on time will help prevent hearing loss and prevent further progression of loss, if any. The final category of an audiogram that needs to be administrated on workers exposed to noise at work is a terminal audiogram/exit audiogram. Terminal audiogram type is administered once the worker leaves the job or changes role. Preserving the terminal audiogram records will help prevent false claims/disputes that may arise in the future.
The use of appropriate hearing protectors in noisy workplace provides the workers with the advantage of not developing hearing loss. Various types of hearing protectors are available in the market. The most common types of available protectors include earplugs, earmuffs, and helmets. Employers owning any form of the industry having a noisy workplace (having noise beyond 85 dB or more) should make the workers use ear protective devices (EPD) without fail. The cost of the EPD’s are to be borne by the employer. The EPD chosen should have a good noise reduction rating (NRR) to be efficient in cutting down noise before it reaches the inner ear. The amount of attenuation provided by EPDs in real life is not precisely the dB value mentioned as NRR. The NRR is measured using C weighing network, and the ears’ responses to sound is more likely to match with the A weighing network scale. In reality, the actual reduction provided by EPD is calculated by taking the NRR number (in dB), subtracting seven, and dividing by two10 (e.g., if the NRR of the EPD is 40 dB, in real life, the amount of protection that an EPD will provide is 40-7/2=16.5 dB). In other words, the amount of hearing protection to a person working in 100 dB noise wearing an EPD with NRR of 40 dB will be 16.5 dB and they are exposed to noise of 83.5 dB after wearing the ear protector, which is well within the DRC for hearing loss. EPDs available in the market are technically adequate to prevent the noise damages that is caused due to a noise level of around 100 dB. If the noise levels exceed 100 dB, a combination of 2 EPDs, namely earplug and earmuff or earplug and helmet, is recommended. Any workplace with continuous noise of 110 dB is not suitable for working even with regular EPDs. Working in such places requires proper administrative controls. Individuals should be provided work shifts and breaks to ensure that they do not develop hearing loss as outlined in the DRC. Adequate quiet periods wherein the noise levels are much lower than 85 dB in-between work, in high noisy areas, need to be provided to the workers to safeguard their ears from hearing loss.
The selection of ear protective devices shall be from a set of EPD with good NRR, and the employee shall be given the opportunity to select the one which seems most comfortable to them. The employer should ensure proper monitoring of the use of EPD. The employee needs to be provided education and training to use the EPDs effectively and shall be provided with the replacement when the EPD is worn out. It is also necessary to maintain proper ear hygiene while using these ear protective devices. The employer shall designate personnel to monitor the effective use of ear protective devices, and essential actions need to be taken if the EPDs are not used appropriately by the employees.
The employer is responsible for keeping a record of all the activities carried out under the HCP, starting from the baseline audiogram. The date of the evaluation and the tester name and calibration status of the equipment needs to be documented appropriately. The follow-up audiograms, namely the monitoring audiograms, need to be administered at regular intervals and should be saved in the client records. Records need to be protected for the entire duration of employees’ employment at a workplace. This documentation serves as the article that helps fight court cases/disputes that may arise during or post the employment tenure.
Noise control at the place of work is accomplished at two levels, 1) making the workplace safer and 2) making the worker safe from noise exposure. To make the workplace safer, all the machinery used in the industries needs to be silenced by means of engineering controls. Elimination of existing noisy machinery and replacing them with quieter ones meeting the industry standards also help make the workplace safer for workers. Workers are made safer to work in noisy areas by scheduling work shifts and ensuring that the individuals are not exposed to higher levels of noise over prolonged work schedules. Personal protective equipment must be provided to all the workers exposed to noise levels above 85 dB. Suitable noise protectors help prevent hearing loss and safeguard the ears of workers exposed to loud noises.
The following conclusions can be drawn from this chapter:
• A good hearing conservation program is to be planned and executed to prevent the harmful effects of noise in employees working in unorganized sector.
• Using an appropriate hearing protector with good NRR will help reduce the impact of noise on hearing structures.
• If the noise levels are higher than 100 dB, a combination of hearing protectors and sufficient quiet-time breaks is necessary to prevent hearing loss.
• The principles of hearing conservation applied in the organized sector are to be enforced in the unorganized sector also, so that the employees are benefitted and safeguarded from developing hearing loss.
• Proper employee training is also essential to educate them regarding the usage of ear protective devices.
• These employees should also be made aware of their work place rights with respect to aspects of hearing and hearing loss.
Noise is defined as unwanted, unpleasant, uncontrollable and unpredictable sound. The noise does not always mean a high-pressure sound, for example the continuous dripping taps may be of a low-pressure sound level, yet it can be considered very noisy especially in silent zones like hospitals. This can be very irritating to a patient in a hospital, especially when there is no back ground noise.
The effects of noise can be auditory or non-auditory. The auditory effects can be acute, which includes acoustic trauma. The acoustic trauma is due to sudden exposure to a very high intensity of noise and can result in immediate hearing loss, while chronic exposure to noise leads to noise induced hearing loss. Non-auditory health effects for noise exposure are perceived disturbance and annoyance, cognitive impairment, sleep disturbance and hypertension. Noise affects the mind and changes the emotions and behaviour in many ways. It interferes with communication and disturbs sleep. The high ambient noise levels, as well as peak noise levels in hospitals, have serious impacts on patient and healthcare staff. It results in sleep loss to elevated blood pressure among patients to emotional exhaustion and burnout among staff.
Learning Objectives
In this chapter we aim to:
1) List the factors to consider when measuring environmental noise in hospital settings
2) Equipment and approaches used to objectively measured noise in hospitals
3) Identify methods to limit the noise
4) The available guidelines as far as noise in hospital settings is concerned as prescribed by Indian standards and WHO
There are many sources of noise in hospital settings. Most of the large public hospitals are generally situated in very crowded place, near main roads with heavy traffic load. The hospitals are often surrounded by a large number of vendors and streets hawkers too. In these situations, the hospital settings can become very noisy. Thus, the noise audible inside hospitals may actually originate outdoors, e.g., vehicle traffic. Another important and main cause of indoor noise is conversations among employees and with patients and their relatives. Other common source of noise in healthcare settings are:
1. ICU Settings–
(a) sound related to humans
(b) sound emitted by medical or technical equipment
(c) sound entering the room from outside
When the ICU is full, noise levels can increase significantly. Noise levels are often excessive, exceeding international guidelines in ICU. Staff conversation is responsible for most of the noise produced; medical equipment, telephones, doorbell and the alarm bells are responsible for causing high levels of noise.
2. Operation Theatre Settings–
Noise is due to various equipments, suction machines, ventilators, drills and powered instruments, autoclave machines and human noise1. Noise pollution in the operating room can reach in excess 120 dBA. If we consider that recommended noise levels within hospitals should be at 45 dBA or less, there is a considerable gap. The average noise levels are between 51 and 75 dBA, and the maximum noise levels were between 80 and 119 dB(A)2, 3. In several studies the highest noise levels were found in the orthopaedic operation theatres. It has been reported that noise in the operating room could cause permanent psychological stress within the staff4. Distractions lead to negative impact in communications amongst the operating room nurses/teams. It is noteworthy that studies have identified miscommunication as one of the leading root causes of error and poor patient outcomes.
Less noise means:
• More concentration
• Easier communication
• Less errors/complications
3. Inpatient and Outpatient Department–
The OPD areas are generally very crowded during day time with very large group of people speaking and chatting in the registration areas and waiting areas. Alarms, televisions, trolleys and phones, as well as staff, visitor and patient conversations are reported as common sources of noise. Patients, visitors, coffee shops/restaurants in OPD area, rolling equipments like patient trolleys, equipment carts, elevators etc. are other sources of noise in hospital OPD areas. HVAC (Heating ventilation and air-conditioning) system which produce continuous low frequency sound. The generators, ambulance and sirens can also be sources of noise in hospital premises. The hospital paging system for healthcare workers and patients is another source of noise. Similarly, the MRI machines can be very noisy and can become uncomfortable for patients. In one of the studies hospital cleaning equipment was the second most important source of noise in hospital settings after generator. It is not necessary that the noise has to be a high intensity sound. For example, a dripping tap may be a low intensity sound level yet it is very annoying and disturbing.
Noise level measurements must be collected for at least one week from Monday through Sunday and in all shifts (morning, afternoon and night) in different hospital areas. Six random measurements must be taken at a time per shift in hospital areas. These areas must include OT, wards, Neonatal Intensive Care Unit (NICU), OPD and Emergency Room. In order to analyse hospital environment noise, a noise decibel meter is required. The noise levels vary with time and there is need to know the overall noise level over a period of time. Hence, Leq is measured. Leq is the Equivalent Continuous Sound Level and represents sound exposure over an elapsed period of time. But getting to this value requires multiple steps and the use of what is known as an Integrating Sound Level Meter. These meters normally do average of all the readings to give a Leq reading.
According to the Noise Pollution (Regulation and Control) Rules (2000) in India, silence zones like hospitals are supposed to have noise level of only 50 dB(A) Leq during day time and 40 dB(A) Leq at night time. An area comprising not less than 100 metres around hospitals, educational institutions and courts may be declared (by the State Government) as silence area/zone for the purpose of these rules5. According to WHO the standards are 40 dB(A) Leq during day time and 30 dB(A) Leq at night time6.
Excessive noise in hospitals reduces the intelligibility of speech and impairs communication, causing annoyance, irritation and fatigue and reducing the quality and safety of healthcare. It has been implicated in the development of intensive care psychosis, hospitalisation induced stress, increased pain sensitivity, high blood pressure and poor mental health.
Hospital noise disrupts sleep of the patients. The machine sounds in particular have a greater negative effect on arousal than human voices. Sound sleep is a highly important restorative process and noise disturbs it. According to the findings of several studies, noise mostly disturbs the sleep of the sick and the elderly. While both quality and quantity of sleep reduce because of noise, it also weakens the immune system and impedes the ability of the human body to generate new cells. Increasing number of medical studies point out that noise causes problems even during the day. According to a study by Vaidyanathan et al, noise can lengthen hospital stays by slowing the recovery rate, as the growing evidence of side effects from noise leads researchers to conclude increased metabolism, quickened heart rate and elevated blood pressure7. Of course, patients are not the only ones to be affected. The caregiver’s concentration can suffer because of noise, increasing their stress levels and fatigue.
Post-hospitalisation recovery is also compromised. In one study from Sweden, coronary care patients treated during noisy periods had a significantly higher incidence of re-hospitalisation than those treated during quieter periods. Noise can have a cumulative effect. When hospitalised for several nights, patients can feel trapped in a stress inducing soundscape, leading to requests for pre-mature discharge and heightened risk of poor recovery and re-admission.
For hospital staff, high noise levels can impact negatively on communication, performance, wellbeing and caring behaviour and can contribute to burnout8. It has been reported that noise in the operating room could cause permanent psychological stress within the staff. It can also be a cause of miscommunication amongst the operating room staffs and can lead to errors in patient management. An astonishing 83% of healthcare staff asked in a survey, published in 2016, thought that noise in the operating room contributed to human error.
Poorly designed environments can result in private conversations between patients and staff or between staff members being overheard by unintended listeners, resulting in unacceptable breaches of confidentiality. At the same time, a poor acoustical environment impedes effective communication by rendering speech and auditory signals less intelligible. This has serious implications for patient safety.
Literature reveals that these noise levels cross the standard limits in most of the hospitals and have auditory as well as non-auditory effects in patients and the hospital staff.
A lot can be done to reduce noise and its effects on patients and staff.
These include earplugs and ear muffs. These can be used by the health workers working in noisy environment. These are not of much use in hospital settings because the health care workers need to listen to patients’ conversation and queries and putting ear muffs will impede such interaction.
The walls and roofs of the OPD may be made up of sound absorbing panels. Engineering and design modifications of the machine and equipment including the barrier creation will reduce noise. Reducing the amount of noise entering into hospitals and building is possible by simply closing the windows. It keeps away annoying sound. It can be the best measure for hospitals situated near main roads. Insulation of acoustic sound panels are some of the primary and most practical ways to reduce noise pollution. Soundproofing can help in blocking the sound vibrations and noise. This is done by improving insulation by installing sound proofing materials on the walls, ceiling and even on the floor. Using double-pane windows can significantly reduce noise inside the building. If some pieces of machinery are creating noise due to vibrations, you can check the noise by applying some noise absorbents to reduce noise. Proper lubrication and better maintenance of machines like suction machines in OT and ICU are beneficial practices to reduce noise pollution and improve efficiency. As lubrication reduces friction between movable parts, it helps to reduce noise.
The key design considerations that must be given attention while designing the patient care areas are
• Providing single-patient rooms as compared to multi-bedrooms are less noisy. The patients and healthcare workers are more comfortable as there the conversation is more private, more effective and confidential. There is no interference by other patients and relatives speaking at the same time.
• Installing high-performance sound-absorbing acoustical ceiling and wall tiles results in shorter reverberation times, reduced sound propagation and improved speech intelligibility. Also, this design measure increases speech privacy as less sound travels into adjoining spaces.
• Removing or reducing loud noise sources on hospital units and educating staff about the impact of noise on patients as well as themselves is effective in reducing noise levels.
• Providing patient examination rooms and treatment areas with walls that extend fully to the support ceiling will prevent voice and noise carrying through ceilings.
• The medical equipments (ventilators, connections for compressed air, oxygen and vacuum, syringe infusion pumps, suction pumps etc.) in ICU can be placed in a sound protective wooden section behind the wall of patient bed. In case of two patients in one room, noise-shielding sideboard between both patients can be installed.
• To reduce human and working related noise, as well as alarms at the bedside, closed working space may be created in between the ICU rooms with glass windows which provides unobstructed patient view with patient monitors and sitting area for health care workers.
• Even simple low-cost measures like fitting of all furniture legs with rubber shoes, replacing metal folders with plastic ones, lubricating the wheels of movable equipment can go a long way in reducing ICU noise9.
It is the addition of background broadband sound (such as white noise) which can be optimised for particular environments to mask and reduce noise induced disturbance. This has been shown in a non-randomised trial to significantly improve sleep of patients in hospitals. Similarly soothing music helps to reduce anxiety and distress among patients. Not all loud sounds are perceived as noise by patients. Some find the sound of the tea trolley pleasing, and some ICU patients welcome ringing telephones as a sign that they are not alone.
An environment devoid of appropriate sounds of hospitals involved in caring for patients is not the optimal outcome. In fact, a completely silent environment will backfire and the patients will feel lonely and depressed. Every single word, buzz or bell will be loud and clear as there will be nothing to stop the sounds from reaching the wrong ears of patients. According to Mazer, the challenge is to design a sound environment in hospital which is not disturbing or invasive. We need to improve the patient and visitor experience by not merely masking noise and other sounds but by adding positive and therapeutic sounds. For example, a water fountain or appropriate soothing music may be played in the background10. This is especially true at night because the environment at that time is really quiet.
Research shows that certain types of music induce relaxation and positive responses, which reduce activity in the neuroendocrine and sympathetic nervous systems, resulting in decreased anxiety, heart rate, respiratory rate and increased temperature. Music is defined as a complex of expressively organized sounds composed of some key elements: rhythm, pitch, harmony and melody. Music therapy or the therapeutic use of music to promote health and well-being in patients has been used in different settings including oncology, maternity, postoperative, intensive care, coronary care and paediatric.
Patients and families need clear information about likely noise levels during admissions so they are better prepared and can consider simple solutions such as headphones with their own choice of audio content. User friendly guides on the potential sources of noise in wards can also help. Education for staff is also needed, to encourage a culture that considers noise reduction an integral part of safe high-quality healthcare. A study by Ramesh et al suggests behavior modifications of the ICU staff for control of noise. This included speaking in low tones, avoiding shouts across the room except during an emergency, holding discussions in a separate room, handling trays and metallic objects gently, putting off the FM radio system, keeping volume of phone at minimum, and tuning alarm volumes using a sound pressure level meter to emit a maximum of 55 dB11, 12.
Sound impacts patients and staff in many different ways. Unwanted sound or noise is a major problem in hospitals the world over. High noise levels negatively impact patient and staff health and well-being and may slow the process of healing among patients.
Niklas suggests 10 steps that hospitals can take up to effectively reduce noise13
1. Form a special committee to study and address noise. Members should educate staff (not only doctors and nurses, but those involved in ancillary departments, like transport), patients and visitors in order to raise awareness of noise and its effects on healing. The committee should also develop and enforce policies related to noise reduction. The program should be evaluated on an on-going basis (e.g., through patient satisfaction surveys) so that measures can be tweaked and added, as needed.
2. Post signs reminding staff, patients and visitors to consider their voice level. They should use hushed rather than normal speaking tones whenever possible and talk only in close proximity to the listener, not from a distance. This strategy can also help to improve speech privacy, which is key in healthcare settings. Some hospitals have topped anti-noise posters with clever acronyms like ‘SHHH’ (Silent Hospitals Help Healing) and ‘HUSH’ (Help Us Support Healing).
3. Provide training on handling loud/disruptive vocalisation by patients and, when applicable, reduce common triggers, such as under-stimulation, overstimulation, immobility, pain or discomfort.
4. Purchase quieter equipment, such as hand towel dispensers and door hardware. Also fix or replace any faulty equipment, such as squeaky carts and creaking doors.
5. Reduce noise from electronic devices: Lower the ringer volume on telephones and set cell phones to vibrate. Also ask patients to use headsets with televisions and all personal electronic devices. Turn off unwatched television sets.
6. Designate ‘quiet time’ during which no routine checks are made unless medically necessary.
7. Restock supplies during the evening rather than at night when patients are trying to sleep.
8. Dim the lights in the evening to encourage quiet and help patients prepare for sleep.
9. Limit or eliminate overhead paging by equipping staff with personal devices.
10. Analyse the use of medical device alarms and reduce their occurrence. Currently, alarms pose one of the biggest obstacles to noise reduction strategies.
Other measures which can be done and do not involve much financial burden on the hospital and can go a long run in decreasing adverse effects of noise are by changing the behaviour of staff and patients14. These include encouraging patients and staff to respect others by turning down the volume on cell phones rings, televisions, radio and other devices. Minimizing cell phone conversations in hospital waiting areas and encouraging others to do the same. Also, unnecessary entry of visitors into patient rooms during quiet hours must be restricted. Reminding staff to be quiet in the patient care setting and wearing soft sole shoes to minimize corridor noise. To make everyone aware testing sound level meters with display of sound levels can be installed that indicate sound levels in the area rooms. This will encourage everyone to be quiet.
Sound control is critically important in healthcare settings as it is known to have deleterious effects on the health of the patients and also interfere with the communication, performance, wellbeing and caring behaviour of the health care workers. There is now enough evidence that improving the acoustical environment in hospitals by careful designing can go a long way toward reducing noise and improving speech intelligibility and effective verbal communication among patients and health workers. Less noise means more concentration, easier communication and less errors/complications by healthcare staff.
This chapter will describe various scenarios in the community setting where noise can have an adverse effect on health. Community noise (environmental noise/residential noise/domestic noise) is defined as noise emitted from all sources except noise at the industrial workplace. (1) Various strategies for limiting noise in these settings will be suggested. The information and strategies may be utilized by healthcare professionals and personnel working in allied sectors for establishing and implementing noise reduction strategies to limit community noise.
Based on ethnographic observations during a community-based survey we have identified scenarios in urban settings where noise levels are above the acceptable level of 55 dB(A). (2) These are traffic noise due to vehicles, trains and take off/landing of aircrafts, power looms inside the house, public address systems, firecrackers, toy weapons, road construction activity, festive and other celebrations, election rallies, leisure events like pubs, clubs, rock music events, sports event, use of ear phones to listen music, television and audio systems at homes, video game consoles, audio systems in vehicles, construction activity in residential areas including bore well creation, air conditioning and ventilation systems and animal created noise like barking dogs.
In the rural setting various scenarios where noise is harmful are agricultural activity, festive and other celebrations, election rallies, power looms inside house, traffic noise due to vehicles, trains and take off/landing of aircrafts, cottage industry near and inside homes, use of ear phones to listen music, television and audio systems at homes and animal created noise like barking dogs.
In community-based settings noise rarely causes hearing loss but has a potential to damage hearing if the exposure is repeated or prolonged. In situations where the power loom is located inside the house and loud impulsive noises due to firecrackers, noise induced hearing loss can occur. In rest of the situations community-based noise is responsible for annoyance, irritation, cardiovascular effects, performance reduction, sleep disturbances and effects on social behavior like its impact on speech intelligibility and communication.
The peculiar characteristics of noise in each of these settings will be described. The maximum recommended noise levels to prevent any health hazard are summarized in a single section. This will assist in choosing the most appropriate method to quantify noise exposure described in Chapter 6, ‘Measuring Sound’. The readers may utilize the information from Chapter 7, ‘Principles of Quantifying Impact of Noise on Health’ to measure the deleterious effects of noise in these settings.
Learning Objectives
1. List various urban and rural settings where noise levels are above the minimum acceptable levels.
2. Understand the concept of guideline value for various community settings.
3. Principles of noise reduction in community and social settings.
Traffic noise affects people traveling long distance on daily basis, residing in homes in the vicinity of roads, railway tracks and airports. At its source, a two wheeler motor cycle, three wheeler auto rickshaw, cars and trucks emit 82, 87, 85 and 92 dB(A) respectively. (3)
Vehicles on the road cause continuous low frequency noise from the engines. The air horns of the vehicles generate impulsive high and low frequency noise. Garbage collection trucks generate extremely loud sounds during loading and unloading when their carriages are detached and fall on the road.
Urban communities located in the vicinity of railway tracks are exposed to intermittent high noise level. Motion of a train creates vibration and low frequency noise. The horns of trains can generate levels above 100 dB (A). Community-based studies in the city of Kolkata has documented high noise levels due to road traffic. (4) A comprehensive review of literature on the effects of road traffic noise on health in the Indian context revealed annoyance as an important effect. (5) High noise levels due to traffic noise has potential health hazards in children. (6)
Take off and landing of aircrafts generates significant noise for those residing in the takeoff and landing trajectory. In certain cities, air force bases are located in the outskirts. Passenger aircrafts create low frequency noise whereas jet fighters can create additional high frequency noise due to their supersonic speeds.
Many urban households run weaving activities using power looms inside their homes. If the loom is weaving a design pattern then the loom has to operate without a break till the entire weaving process is complete. For this reason, the loom is run for long hours even at nighttime. It creates predominantly low frequency noise with intermittent high frequency levels. Fig 17.1 shows the power loom being operated inside a urban household.
Power loom being operated inside an urban household in Bengaluru.
Public address systems are commonly used in places of worship, festivities and election rallies. Depending on the nature of music or type of information being broadcast the noise levels may be high or low frequency. These noises are usually intermittent in nature. Also, firecrackers are used to celebrate festivities. They generate very high noise levels which is painful for the human ear. Two Indian studies have documented the high noise levels of toy weapons and firecrackers. (7, 8)
Pubs, discothèques, clubs and rock music events generate extremely loud noises. Many of these activities are held in the late evening time. For residents of houses in the vicinity of these events, considerable degree of annoyance is experienced. Workers and customers in these settings are exposed to extremely loud noise especially low frequency sounds. Music and dance classes are held in households. In urban areas where houses have a partition, sounds get transmitted across the partitions to neighbours which cause significant annoyance.
Sports activities like cricket matches held near or in grounds located in residential areas create a lot of noise generated by the crowds cheering the teams. This is compounded by horns and noise making devices like vuvuzela, which create very high pitch sounds.
Personal audio systems like home theatre consoles are an important health hazard if played in loud volumes. Use of ear phones especially ear bud type of headphones could be a cause for concern. In some households, television is continuously played. This could be a cause of annoyance for the neighbours.
Technology and animation has created video games that are a source of entertainment for children as well as adults. Many of the video games consoles are linked to home theatre audio systems to provide a special experience. Families invest in these devices for entertainment at home. Toy weapons like guns that emit noise create a high pitched shrill noise. The noise generated by these devices can be potentially harmful for the users especially children. (7)
High noise generated by audio systems in cars and sports utility vehicles is detrimental for the passengers. The high bass is a source of low frequency noise.
Construction activities generate considerable noise levels that can affect the lives of people living in homes near these activities. In urban areas, metro rail construction is an important source of annoying noise especially during night when considerable amount of activities are performed.
There are two types of air conditioning and ventilation systems: systems where compressors and ducts are in close proximity and those in which the compressors are located at a distance from the ducts that deliver treated air. In the first type of system, low frequency noise is generated by both the compressors and exit ports of the vents, whereas in the second type of systems the exits of the vents solely contribute to the noise. Compressor noise is mainly low frequency noise.
In rural areas, agricultural activities take place in the fields located near the homes of people. Machines used for processing the raw agricultural produce like threshers can generate significant level of noise in the houses in their vicinity.
During festivals, other celebrations like social gatherings and election campaigns loud speakers are often used to play music and messages delivered by the campaigners. The blaring sounds of these audio systems create high decibel noise in residential areas. Firecrackers generate extremely loud noise which is painful to the ear. Some firecrackers like rockets create a shrill high pitched noise during launching.
As in urban areas, power looms are located inside rural households. It is a good source of income generation. For completion of a design pattern on the fabric, the loom has to be continuously operated during day and night. This may be harmful for the residents and an irritant for the neighbours.
In rural areas some localities are beside the highway and railway tracks. Vehicular movement on the roads and rail tracks generate noise that can affect the persons living in these houses, especially at night time.
Conventionally airports were located at the fringes of cities. With an enormous increase in air traffic, the airports have been relocated to outskirts of cities. Many of the outskirts are rural areas. So the households located in these areas are exposed to loud noise of aircraft take off and landing.
For income generation, many rural households have various categories of cottage industry located inside their households. Many of these activities involve machinery which generates intermittent or continuous noise inside the house. Some common activities are pickle making and grinding masala powder.
With globalization, urban lifestyle and its amenities have pervaded into rural communities. Along with the benefits of modern amenities, it has also made people use personal hearing gadgets like ear phones. Long term use of these gadgets may be harmful to the listeners. Television with loud audio systems is also a cause for concern in rural households.
Guideline value is the maximum permissible sound for a given environment in the community setting. (8) The night time levels should be at least 5 dB(A) below the guideline value. The guideline values for various settings are as follows:
Outdoor living area: The guideline value is 55 dB(A). Levels above this cause serious annoyance for the residents.
Indoor dwellings and inside bedrooms: Levels should not exceed 35 dB(A) as it leads to moderate annoyance, affects speech intelligibility and sleep.
Outside bedrooms: The maximum permissible level is 45 dB(A). Levels above this measure causes sleep disturbances.
School classrooms and pre-school indoors: Levels above 35 dB(A) affects speech intelligibility, disturbance of information extraction and message communication.
Pre-school sleep areas indoors (for children): The maximum permissible level is 30 dB(A) and noise higher that 30 dB(A) causes sleep disturbance among children.
Outdoor playground in schools: Levels above 55 dB(A) causes annoyance among children in these settings.
Indoors of hospitals: The maximum permissible level in these settings is 30 dB(A) above which sleep disturbances occur.
Hospital treatment rooms: In these settings the noise levels should be as low as possible much below the 30 dB(A).
Indoors and outdoors of shopping areas and traffic: Levels above 70 dB(A) causes hearing impairment as a long-term effect.
Ceremonies, festivals and entertainment events: In these settings the levels should not exceed 100 dB(A). These levels may cause hearing impairment if exposed for long hours.
Public address systems indoors and outdoors: 85 dB(A) is the guideline value for public address systems. Prolonged exposure to levels above this may cause hearing impairment.
Music and other sounds through headphones and earphones: The free field values for these systems should be within 85 dB(A) to prevent hearing impairment.
Impulse sounds from toys, fireworks and firearms: These settings are characterized by sudden impulse sounds which are harmful for hearing. The maximum permissible value is 120 dB(A).
Outdoors in parklands and conservation areas: Here there should not be any external sounds so as to preserve the tranquillity. The effects of mining noise on biodiversity has been documented in an Indian study. (9)
Implementing noise reduction strategies in community settings is a challenging task. This section will describe the possible methods that may be employed. People and organizations working for noise reduction in communities have to adapt and adopt these based on the specific context.
The broad principles of any noise reduction strategy are noise measurements, reducing noise at the source, limiting reverberations in the closed space, blocking sound at the receiver level and measuring/monitoring harmful effects of high noise levels. The readers may utilize the information from Chapter 7, ‘Principles of Quantifying Impact of Noise on Health’ in Part II to measure the deleterious effects of noise in these settings and also measure sounds. The main factor that determines quantification of sound is the nature of the noise. Noise can be continuous, impulsive and continuous with interspersed impulses (mixed type). Based on this the noise quantification strategy is planned..
For reducing community noise levels involving people in the community is crucial. Imposing laws framed by the pollution control board has a temporary effect. Many a time people follow the rules till a person from the enforcing authority is present. For consistency in following the rules, the community has to take accountability for enforcing these regulations. The first step is to create awareness among the community leaders who influence opinion. They can be made aware of the harmful effects of noise. Scientific information has to be explained in a simple and easily understood language. Role plays, street plays, demonstrations and storytelling methods may be employed. An ethnographic observation of various settings in the community where noise is potentially harmful is a useful resource on which these sessions may be planned. The opinion leaders must be given charge of implementing noise reduction programmes in the community. These leaders have to organize a group of community based volunteers predominantly youth who can conduct a noise survey in the community. A simple sound level meter costing Indian national rupees five thousand may be employed to perform the noise survey. A training session has to be organized covering the following aspects explained in an easily understood language: importance of conducting the noise survey, sound and its properties and technique of using the sound level meter. Scientific jargon should be avoided. Physical demonstrations using sound generating equipments like drums, whistles, rattles, bells, motors and vehicle horns should be used to explain various types of noise. In controlled situations, the sound level meter should be used to demonstrate the techniques of using it. Figure 17.2 shows a basic sound level meter. The main steps to use the meter are as follows: switching on the power button, ensure the setting is in dB (A), wait for the reading to stabilize it by holding it stationery for a while and noting down the reading. Using cycle mounted sound level meters has been recommended by an Indian study as a bicycle can be easily taken through all the narrow lanes in the community. (10)
After completing the noise survey the volunteers have to create a noise map of the urban or rural community. The map should clearly indicate residential areas where noise levels exceed the recommended 55 dB(A). There should be a description of the characteristics of the noise. Is it continuous, impulsive or mixed type? Based on the opinion of expert, potentially harmful effects of noise should be understood by the volunteers. These volunteers should organize small community-based educational sessions for all the people exposed to high noise levels. It should include both people responsible for generating the noise and those affected by noise pollution.
In these community-based sessions, people should be involved in a brainstorming session to examine possible methods to reduce noise which is harmful to all those exposed to it. Surprisingly the people who create noise may get aware that they are also affected by the noise that they create and it may have significant consequences. The volunteers can facilitate the session by giving some technical inputs like methods to limit noise like planting trees and shrubs along roadsides, introduction of silent zones around schools and hospitals, ban on air horns, enforcement of noise control regulations, use of silencers in auto rickshaws, bypass roads for heavy vehicles, restricting movement of heavy vehicles at night through residential areas, installing sound proof windows, thick cotton curtains, proper planning of residential areas and lubricating moving parts of machines on a regular basis. Demonstration of various types of ear protection devices and technique of using them should be performed. This is very relevant to those who have cottage industries and power looms inside the house.
Compliance with noise reduction strategies is a challenging domain. It involves shifting the behaviour of people. Behaviour change occurs by creating a culture of silence. Culture is defined as a set of practices followed in the community. The people in the community are primarily accountable for creating this culture. The volunteers have to use examples to highlight this powerful concept using examples. One example is culture of cleanliness, which ensures that people do not litter garbage. Similarly, when a culture of silence gets created, the new people who walk into this culture get conditioned to reduce noise.
After the set of strategies have been selected, the volunteers have to ensure that the community starts acting on them. Innovative methods should be employed to create a momentum for enforcing these strategies. There can be a competition organized for the most silent street or ward. Social media may be utilized to announce the areas that have ensured that noise levels remained within acceptable limits. The residents can share the experience of having a quiet environment in terms of sleep quality, performance improvement and ease of communication.
The groups of volunteers have to monitor consistency of compliance with these strategies on a regular basis. Ensuring that community noise remains within the recommended levels is an on-going process.
Sound level meter to measure noise levels.
• The recommended noise levels in residential settings is 55 dB(A)
• Community noise (environmental noise/residential noise/domestic noise) is defined as noise emitted from all sources except noise at the industrial workplace
• Guideline values are prescribed for various community settings and noise reduction strategies should target these values
• Various sources of community noise in urban settings are traffic noise due to vehicles, trains and take off/landing of aircrafts, power looms inside the house, public address systems, firecrackers, toy weapons, road construction activity, festive and other celebrations, election rallies, leisure events like pubs, clubs, rock music events, sports event, use of ear phones to listen music, television and audio systems at homes, video game consoles, audio systems in vehicles, construction activity in residential areas including bore well creation, air conditioning and ventilation systems and animal created noise like barking dogs
• Various sources of community noise in rural setting where noise it is harmful are agricultural activity, festive and other celebrations, election rallies, power looms inside house, traffic noise due to vehicles, trains and take off/landing of aircrafts, cottage industry near and inside homes, use of ear phones to listen music, television and audio systems at homes and animal created noise like barking dogs
• Community involvement and participation is critical to ensure compliance with noise reduction measures.
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