Addressing the noise pollution problem

Some estimates of the direct costs due to ill-health from noise pollution put this figure at as much as 2 percent of Gross Domestic Product (GDP) of a country (i.e. negating the supposed benefit of the much touted proposed Tata investment). The psychological and social cost is difficult to assess.

What price-tag can be placed on an environment where conversation is easy and where children are able to read quietly and are free to concentrate on their school work? An important investigation by V. Kiernan of Cornell University shows that children brought up in noisy areas have poorer reading skills and find it more difficult to recognize and understand human speech than those brought up in quieter areas. Nervousness and depression are common psychological reactions to noise. The eye has a very effective means of adjusting to light, but people never get "used" to noise. Instead, they usually adjust their mental attitude rather than hearing compensation. Subconscious frustrations can result when noise is endured, but the body system cannot adjust to it.

Sound level is one of the most important parameters when predicting performance effects. The level of noise necessary to produce adverse effects is greatly dependent upon the type of task. Simple tasks remain unaffected at noise levels as high as 115 decibel, dB (very loud) or above, while more complex tasks are disrupted at much lower levels. Until fairly recently, the level at which the effects are first seen was thought to be quite high for most conditions, but a summary of recent research points to effects at much lower levels, even as low as 80 dB (a loud television) for intermittent noise.

The ears provide two warning signs for overexposure to noise: temporary threshold shift and ringing in the ears (tinnitus). After leaving a noisy area or piece of equipment, many people commonly experience both of these symptoms. The temporary hearing loss is difficult to detect unless a hearing test is performed. Hearing usually returns almost completely in 12 to 14 hours if there is no more noise exposure. Any amount of hearing that does not return becomes a permanent threshold shift or permanent noise induced hearing loss (NIHL). With repeated exposure, the effects are cumulative.

The permanent damage that occurs from overexposure to noise results in a hearing loss that is annoying and deceptive. The listener is aware that someone is speaking but cannot understand the message. The ability to identify the source of sound is greatly reduced and the listener seems inattentive. Noise-induced hearing loss is a major problem because people are unaware of its warning signs and effects until it is too late.

Noise pollution in Bangladesh
Bangladesh urban habitats are regarded as "noisy" by international standards. A number of travel guidebooks describe the country in this way. In fact the level of noise in Bangladesh both by day and by night has become truly appalling and it is affecting the health and welfare of the nation.

Two kinds of noise pollution are generally recognized. Firstly there is "occupational noise" which affects workers in the course of their jobs and is due to the work environment and/or to the machinery which they must operate. Secondly there is "environmental noise," such as traffic noise or noise from a loud radio, and which is not work related.

Occupational noise is already recognized as a problem and further education on noise induced hearing loss (NIHL) would however be worthwhile to encourage the use of whatever protective head-gear (usually ear muffs) is provided by the employer.

The second kind of noise is more difficult to deal with and is a major problem. The actual sources of the noise pollution are: police and ambulance sirens, car horns, heavy traffic, stationary sound systems, mobile sound systems ("boom-box" cars), radios, places of prayer, public meetings, motorbikes, mobile loudspeakers, vehicle repair workshops, construction work, factories, loud voices, airplanes, motorized boats, and others. A full environmental audit would, of course, be required to place these in their proper order of importance.

While noise emanates from many different sources, transportation noise is perhaps the most pervasive and difficult source to avoid in society today. Road traffic noise is a major contributor to overall transportation noise. A broad-based effort is needed to control transportation noise. This effort must achieve the goals of personal privacy and environmental quality while continuing the flow of needed transportation services for a quality society.

Effective control of the undesirable effects of transportation noise requires that land use near major roads be controlled, that vehicles themselves be quieted, and that mitigation of noise be undertaken on individual road projects. People are largely unaware of the dangers of noise pollution and often unmindful of the annoyance that loud noises can cause.

Land use control
Essentially the central government has the primary authority to regulate land use planning or the land development process. The local government institutions seldom can use their power to regulate land development in such a way that noise-sensitive land uses are either prohibited from being located adjacent to a highway, or that the developments are planned, designed, and constructed in such a way that noise impacts are minimized. Not withstanding the laws, the entire issue of land use is extremely complicated with a vast array of competing considerations entering into any actual land use control decisions. For this reason, it is nearly impossible to measure the progress of using land use to control the effects of noise.

Source control
It is time that we have a government agency with authority to establish noise regulations to control major sources of noise, including transportation vehicles and construction equipment. Such an agency is required to issue noise emission standards for motor vehicles plying on the road, etc. and to enforce these noise emission standards.

In the United States, for example, EPA established regulations which have set emission level standards for vehicles plying on their highways, at 80 decibel steady average (dBA) for new vehicles and 87 dBA for existing vehicles.

Traffic management measures can reduce noise problems too. For example, if acceptable alternative truck routes are available, trucks can be prohibited from certain streets and roads, or they can be permitted to use certain streets and roads only during daylight hours. Traffic lights can be changed to smooth out the flow of traffic and to eliminate the need for frequent stops and starts. Speed limits can be reduced, but a 32 km-per-hour reduction in speed is necessary for a readily noticeable (5 dBA) decrease in noise levels.

Law enforcers must first obey the law
With a view to improving the law and order situation in the country, the police department imported a number of vehicles with siren systems. While plying on the roads these vehicles blow their sirens, most often unnecessarily, at such a high pitch that it will create irreversible hearing impairment to the occupants of the vehicles as well as to the people at large. The police while escorting VIPs keep on blowing the sirens loudly even when there are traffic jams and knowing fully well that no way they could pass. Many microbuses are fitted with siren like horns and they blow them at 100 or more dB to the annoyance of many.

Recently I was passing by the Tejgaon-Gulshan link road. Traffic was very heavy. Behind me was a costly SUV continuously and loudly blowing a police-like siren fully aware that it was impossible to make way for him. At one stage traffic was at a complete stand still, yet the siren was on. I got down, tapped at the dark window of the wealthy occupant at the back to very politely tell him to kindly ask the driver to stop the noise, and also hinted it was illegal for a private citizen to install a police siren in his vehicle. My friends told me later that it was foolhardy to do that and that there are a number of such vehicles in Dhaka.

Civil society response
Hearing loss is 100 percent preventable, but once acquired, hearing loss is permanent and irreversible. Hence, I would advocate that a civil society forum be mobilized to create awareness about sound pollution and its prevention. The newspaper has championed and addressed many social issues, given the present state of sound pollution in the country, it can start awareness campaigns utilizing young people like the boy scouts, students, etc. Such a campaign could aim at achieving:
1. Ban blowing of car horns in all urban areas as well as populated rural areas like bazaars and schools.
2. Permanent removal of hydraulic horns from all kinds of transport vehicles.
3. Fixing a maximum noise level of 80 to 90 decibel (dB) for vehicle horns, sirens, etc.
4. Ban trucks and heavy cargo vans from passing through residential areas.
5. Induction of awareness training and promotion of using protective devices in industries.
6. Inclusion of noise related information in secondary school level text books.
7. Introduction of hearing tests in schools.
8. Ban use of loudspeakers at night.
9. Ban use of any sound making devise that is audible at a distance beyond 100m from its source.
10. Encourage law enforcers to be the best practitioners of the law.

Time has come to address this issue which is no less a social menace than HIV/AIDS, malaria or tuberculosis.

The writer is a past president of FICCI and occasionally writes on social issues.