Noise pollution and its management

Introduction

Noise is an integral part of our day-to-day life as we come across noise almost everywhere including workplace, homes, schools and public places. Some of the sources of noise cannot be blocked, but we can modify the way we react. However, a remedy is possible in almost all the scenarios irrespective of the source of the noise. Prolonged exposure to high-intensity noise can harm our body systems irreversibly. Noise levels are measured by the unit decibels and the noise levels exceeding 150 dB (decibels)  is dangerous. In India, the Prevention and Control of Pollution act came into force in the year 1981 which regulates the activities that cause undue noise.

 

 

Definition of noise pollution

The word noise is derived from the Latin word ‘Nausea’ meaning sickness or making someone feel like vomiting. Noise pollution is the excessive noise produced from any source affecting the mood, health and well-being of human beings. The range of noise can be 1dB-140dB and our ears can sense as low as 1 dB of noise. Noise as a phenomenon is understood differently from different perspectives. As far as the physics is concerned, it talks about the levels of noise, unit of measurement, factors affecting the sound transmission but on the biological context; noise is all about the biological and psychological impact that it causes.

 

 

Perception of noise

Noise pollution is more of a subjective feeling as the perception of the noise varies between each individual. An individual at 40 dB may feel disturbed while the other may take it for granted, hence each person react to the noise differently. To look into the magnitude of the problem, noise is really a serious issue in the modem day`s lifestyle. Uncontrolled exposure to the noise causes a deleterious effect on the person`s body systems, emotions and personality.

 

 

Measuring noise levels

The frequency of a sound wave is measured in hertz (Hz). Sound waves are the result of vibrations travelling from a point to another through the air. Greater the wind force quicker the transmission, however, there are other factors interfering in the production and transfer of noise. Sound is described in terms of the loudness, amplitude and pitch (frequency) of the sound wave that travels between 2 points.    The lower and the upper threshold of sound that the human ears can tolerate is 0-140dB. Nevertheless, the noise beyond 85dB  causes deafness.

 

 

Noise levels of different sources

Exposure to noise above 85 dB (adjusted decibels) over a long period of time may cause hearing loss. Both the intensity and duration of exposure to noise determines the possible effects. Research shows that the maximum exposure time at 85 dB must not be more than 8 hours. Similarly, if someone is exposed to the 11o dB for 8 hours, he or she should not be exposed for more than 89 seconds at one stretch.  When it comes to the audibility of noise, ZERO (0) is the softest sound, 10 dB is the noise produced during normal breathing, 20 dB is when someone whispers at 5 feet (1.52 m) distance . Furthermore, the noise of heavy rainfall measures about 50 decibels while our normal conversation measures 60dB. Some of the heavy industrial machines and cracker sounds produce as high as 120 decibels which is the threshold.

 

Zones  

Permissible noise level standards in the daytime (dB)

Permissible noise level standards at night (dB)

Industrial Zone

75

70

Commercial Zone

65

55

Residential Zone

55

45

Silent Zone

50

40

 

 

Causes (sources) of Noise Pollution

Noise is released by a variety of sources. Many people habituated to the routine sources of noise in their daily life. Some of the regularly exposed sources could be noise at domestic levels, industrial setups and the noise from trains and aeroplanes. Sounds can also be produced from classrooms, vehicles,  loudspeakers, public noise, industrial machines and crackers. Some of the specific cause of noise are enlisted as under.

  1. Noise is produced from heavy machinery due to the outdated and faulty installation. Some of the poorly designed and loosely installed spare parts can also cause undue noise.

  2. The assemblage of a huge audience in a congested hall.

  3.  Urban noise due to the poor infrastructure, congested buildings, sound-producing sources near public gatherings, lack of noise-proof areas.

  4. Vehicular traffic is one of the biggest sources of noise pollution in India. Though the traffic department sets certain norms but most of the time people fail to comply with them.  Many vehicles emit noise well above the threshold.

  5. Public construction and major projects in and around the residential areas can have a significant effect.

  6. Noise from trains or air traffic. 

  7. Noise from grinders, mixers, vacuum cleaners and pressure cookers.

  8. Diwali crackers.

  9. Mining, military activities (gun fires).

  10. Keeping high volume while using earphones and headphones 

  11. Impulsive sounds from toys, fireworks and firearms.

 

 

The negative impact of noise pollution

Noise affects us in a variety of ways. Noise beyond the recommended levels can impact physically, physiologically, socially and emotionally. Hence, it is recommended to follow the standard guidelines prescribed by the pollution boards and WHO.  Some of the specific ways in which noise affect us are;

  1. Prolonged exposure to both the high and low noise levels can interfere with the speech development in children.

  2. Many people have lost their hearing while being exposed to a high range of noises.

  3. Noise affects the sleep and rest pattern hence it is advisable to choose a sleeping room located at noise-free areas.   

  4. Noise can cause diseases such as hypertension, heart attack, chest pain and other cardiovascular disorders.

  5. Behavioural and psychophysiological effects such as poor attention and concentration, slowness in the learning, irritability, headaches and many psychiatric illnesses are due to prolonged noise.

  6. Noise pollution can cause hormonal imbalance.

  7. Louder noise is linked with changes in the adrenaline-stress hormone levels, altered blood magnesium levels, poor immunity, gastrointestinal disturbances such as loose motion

  8. Sound pollution causes poor school performance among school going kids and teenagers. Many children complain of memory issues, poor thinking and distractive learning pattern as a result of exposure to unnecessary noise levels.

  9. Loud and prolonged noise influences our social behaviour.

  10. Road traffic accidents can occur as a result of distractive noise.

 

 

Prevention and management of the effects of noise pollution

  1. The best way to manage the effects of noise pollution is by avoiding the source of noise or finding an alternative. Use earphones and speakers by adjusting volumes so that it won't be annoying for others.

  2. No sound zones should be set to schools, hospitals, holy places and residential areas.

  3. Scientifically proven design and acoustics for all the commercial buildings is a must.

  4.  Periodic inspection of industrial machines by the concerned agencies.

  5. Avoid the unnecessary honking in public places like schools, temples and hospitals.

  6. Soundproof construction material should be used while building the living rooms.

  7. SILENT signposts must be installed wherever necessary.

  8. In unavoidable circumstances, use cotton plugs to soothe the effect of noise.

  9. Develop a strict regulatory framework as per the recommendations given by the pollution control boards.

 

 

Permissible noise levels according to WHO

Specific environment

Sound in dBs

Timebase [hours]

Outdoor living area

55

50

16

16

Dwelling, indoors

Inside bedrooms

35

30

16

8

Outside bedrooms

45

8

School classrooms and pre-schools, indoors

35

during class

Pre-school

Bedrooms, indoors

30

sleeping -time

School, playground outdoor

55

during play

Hospital, wardrooms, indoors

30

30

8

16

Industrial, commercial, shopping and traffic areas, Indoors and Outdoors

70

24

Ceremonies, festivals and entertainment events

100

4

Public addresses, indoors and outdoors

85

1

 



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