Noise pollution

Introduction

Sound/noise pollution

Sound is a ubiquitous aspect of human and animal existence, serving as a crucial medium for communication and entertainment. It also functions as an effective alarm system. While low-volume sounds are generally pleasant, loud sounds are considered unpleasant and are commonly termed as noise. Noise can be defined as an unpleasant and unwanted sound.

Noise is often defined as “unwanted sound,” but this definition is subjective due to the fact that what one person considers sound, another might perceive as noise. Perhaps a better definition of noise is “wrong sound, in the wrong place, at the wrong time”..” The 20th century has been characterized as the “Century of Noise.” Noise has emerged as a significant stress factor in the human environment. The term “Noise Pollution” has been coined recently to denote the extensive cacophony of sounds generated in modern life, contributing to health hazards.

Sources of noise pollution

Major sources of noise pollution include:

(i) Industrial Sources: Technological advancements and industrialization have led to the creation of noise pollution. Industries such as textile mills, printing presses, engineering establishments, and metal works contribute significantly to noise pollution.

(ii) Transport Vehicles: The automobile revolution in urban centers has emerged as a major source of noise pollution. The increasing traffic has resulted in traffic jams in congested areas, where the constant honking of horns by impatient drivers can be disruptive to all road users. Noise from airplanes has become a growing concern in large cities, especially when airports are located near residential areas, causing airplanes to pass over populated regions. Additionally, heavy trucks, buses, trains, jet-planes, motorcycles, scooters, mopeds, and jeeps contribute to the overall noise pollution in various settings.

(iii) Household: The household, functioning as a small-scale industry, constitutes a source of various indoor noises such as door banging, children playing, infants crying, furniture being moved, and loud conversations among inhabitants. In addition, household entertainment equipment such as radios, record players, and television sets contribute to indoor noise pollution. Domestic appliances like mixer-grinders, pressure cookers, desert coolers, air conditioners, exhaust fans, vacuum cleaners, sewing machines, and washing machines are all indoor sources of noise pollution.

(iv) Public Address System: Religious functions, ceremonies, births, deaths, marriages, elections, demonstrations, or commercial advertising all utilize public address systems, thereby contributing to noise pollution in their own way.

(v) Agricultural Machines: Mechanization in agriculture, with the use of tractors, thrashers, harvesters, tube wells, and powered tillers, has made farming more efficient but has also introduced significant noise pollution to rural areas.

(vi) Defense Equipment: Considerable noise pollution is introduced into the atmosphere by the operation of artillery, tanks, rocket launches, explosions, military aircraft exercises, and shooting practices. The loud screams of jet engines and the occurrence of sonic booms can have a deafening impact on the ears.

(vii) Miscellaneous Sources: Automobile repair shops, construction sites, blasting, bulldozing, and stone crushing activities are additional sources of noise pollution.

Noise pollution level

Level in decibels	Effects
Upto 23	No disturbance
30-60	Stress, tension, psychological (illness, heart attack) effects especially at upper range.
60-90	Damage to health, psychological and vegetative (disturbance in stomach-gall function, pains in muscles, high blood pressure, disturbance in sleep­ing)
90-120	Damages to health and ontological (ear diseases) ef­fects
Above 120	Painful effects in long run.

Effects of noise exposure

The effects of noise exposure can be categorized into two types:

Auditory

• Auditory fatigue: This effect becomes apparent in the 90dB region and is most pronounced at 4000 Hz. It may be accompanied by side effects such as whistling and buzzing in the ears.
• Deafness: The most severe pathological consequence of noise exposure is deafness or hearing loss. In the early stages, the victim may be generally unaware of it. Hearing loss can be either temporary or permanent. Temporary hearing loss occurs after a specific exposure to noise, and the disability typically resolves within a period of time, usually within 24 hours following the noise exposure.

Non auditory

• Interference with speech: Noise disrupts speech communication, particularly in everyday situations where frequencies causing the most disturbance to speech lie in the 300-500 Hz range. These frequencies are commonly found in noise generated by road and air traffic. For optimal speech intelligibility, it is considered necessary that the speech sound level surpass the speech interference level by approximately 12dB.
• Annoyance: Annoyance is a primary psychological response to noise. Neurotic individuals tend to be more sensitive to noise than balanced individuals. Workers exposed to higher intensity noise in occupational settings often experience irritation, short temper, impatience, and are more likely to resort to agitation, leading to disruptions in production.
• Efficiency: In situations requiring mental concentration, a low level of noise is preferable. Reduction in noise has been shown to increase work output by improving mental concentration and overall efficiency.
• Physiological changes- Temporary physiological changes occur in the human body due to noise exposure, including:

1. Elevation in blood pressure
2. Increase in intracranial pressure
3. Rise in heart rate and respiration
4. Increased sweating
5. Symptoms such as giddiness, nausea, and fatigue
6. Constriction of pupils affecting color perception and diminishing night vision

In addition to its impact on health, noise also plays a significant role in causing economic losses. A wide range of economic impact by affecting productivity, health-related costs, turnover, regulatory compliance and decrease in property values. Addressing noise pollution in workplaces and communities is not only essential for protecting human health but also for sustaining economic well-being.

Control of noise pollution

To effectively control noise pollution, a multifaceted approach is essential. This involves careful city planning and stringent regulations for vehicular activities. The following measures should be implemented:

Careful city planning:

• Zoning: Divide the city into specific zones, ensuring a clear separation of areas dedicated to industry and transport.
• Green belts: Create green belts to separate residential areas from main streets. Residential structures should be positioned at least 15 meters away from roads, and the intervening space should be densely populated with trees and bushes.
• Main street widening: Enlarge main streets to diminish the intrusion of noise into dwellings.

Control of vehicles:

• Routing restrictions: Heavy vehicles should be directed away from narrow streets, preventing congestion and excessive noise.
• Traffic reduction: Minimize vehicular traffic on residential streets to mitigate noise disturbances.
• Horn regulations: Prohibit the indiscriminate use of horns and the installation of pressure horns to maintain a quieter environment.

Enhancing acoustic insulation of buildings:

• From an acoustic perspective, constructing detached buildings is preferable to a single large or continuous structure.
• Prohibit installations that generate noise or disrupt occupants within residential dwellings.
• Incorporate sound-proofing measures in buildings where necessary to minimize external noise intrusion.

Industrial and railway considerations:

• Implement noise control measures at the source within industrial facilities.
• Designate specific areas, located outside residential zones, for industries, railways, marshalling yards, and similar installations.
• When meeting these requirements proves challenging, establish protective green belts between installations and residential areas to mitigate noise impact.

Protection of exposed individuals:

• Workers consistently exposed to noise levels exceeding 85 decibels in frequency bands above 150 Hz should use hearing protection.
• Implement a rotation system for workers, moving them from noisy areas to quieter positions within factories.
• Conduct periodic audiogram check-ups and provide ear protection, such as earplugs or earmuffs, as needed.

Legislation:

• Many states have adopted legislation encompassing controls applicable to a wide range of sources.
• Workers retain the right to seek compensation if they experience a loss of speech understanding ability due to noise exposure.

Education:

• The success of any noise abatement program hinges on public participation.
• Therefore, comprehensive education through various media channels is essential to raise awareness about the community hazards associated with noise.