Cause Of Noise Pollution

Causes of Noise Pollution

The major sources of noise are


Use of Television and Radio	Railways	Use of loudspeakers	Industrial activities	Aircraft

- Courtesy by : C.P.R.Environmental Education Centre, Chennai

Causes of Noise

Transport noise
Social Noise
Industrial Noise
Noise in the Sea

Transport noise :

There's no getting around it. Transport is a necessity, and because of this there are very few places in the United Kingdom where transport noise cannot be heard. An industrial society depends on mechanical transport for the efficient distribution of people and goods between dwellings, schools, shops, offices, factories, leisure centres, and many other places.

Categories of Transport Noise :

Road Noise: This mainly comes from cars,buses, lorries, vans and motorbikes, and each of these makes noise in a variety of different ways. Typically the things that bother people the most are engine starting, gear changing, car stereos, brakes and tyres. Half the responsibility of keeping their vehicle quiet lies with the driver, making sure the car is in good working order, for example; that the brakes don't squeak. Also driver's must be aware that their vehicle is likely to cause a noise, and drive it in a way that reduces the annoyance to others; not racing along quiet residential roads, avoiding driving at night, unless necessary.
The simple solution is to make people park their cars a few minutes walk away from residential areas, but when one suggests this to people, it turns out that they would prefer to occasionally be disturbed by noise, rather than have to walk to their car, or the nearest bus stop.
Rail Noise:
Noise from trains is really a bit odd. If one compares two people, exposed to the same amount of noise, one from cars, the other from trains, the car person is far more likely to complain. No-one is quite sure why this is, but it could be that the trains are seen as more useful, or that their noise is unavoidable. Whatever the reason, there is far less pressure on the railways to reduce their noise, than for road vehicles, and aircraft.
Air Craft Noise:
This is a major problem to those people who live near a busy commercial or military airport, but for most people aircraft noise goes unnoticed.

Airplane noise can be a much greater disturbance to sleep than other noises. Research indicates that near a major airport, the number of people awakened by airplanes is about 50% greater than the number awakened by other noises. Mumbai has one of the busiest airports in the country. Most people living near the airport have to deal with the noise disturbance caused by planes landing or taking off every three to five minutes. People living close to the airport have to bear with noise levels up to 110 decibels. Says 29-year old Anjali Kapoor, a Computer Analyst who lives close to the Domestic Airport in Mumbai, "Every time a plane takes off the conversation in the house automatically becomes louder. We cant hear the television or the phone so we have to increase the volume to hear it well. Besides your sleep gets disturbed at least twice or thrice practically every night."
Aircraft noise is not simply a problem for those trying to sleep. Studies have demonstrated that exposure to high levels of aircraft and environmental noise can adversely affect reading ability in school-age children. Sleep disturbances are probably the most widespread source of annoyance caused by noise.
Studies on aircraft noise have also concluded that elevated blood pressure, heart disease, and psychological trauma are direct consequences of noise exposure. Although these associations have been reported, others contradict or do not bear them out. Hypertension, heart disease and psychological trauma, as well as irritation and annoyance can be engendered by a variety of risk factors or by several operating simultaneously.

Social noise :

Of all sorts of noise, neighbourhood noise is the greatest source of noise nuisance and complaints. A survey carried out in the UK in 1986/87 estimated that 14% of the adult population was bothered by neighbourhood noise, compared with 11% from road traffic noise, and 7% bothered by aircraft noise.

The sources of neighbourhood noise, in order of number of complaints, was Amplified music; Dogs; Domestic activities; Voices; DIY; Car repairs; with 10% complaining about something else.

Engineers strive to make these complains less frequent. Often there is little engineers can do to reduce the noise at source. People are people, and will make a noise. What is done is to stop the noise, as it travels from from the source to the listener. Double glazing and better insulated walls are two low-tech solutions to the problem. Hi-tech solutions include the active control of sound: For every noise, making an anti-noise, and having the two cancel out, but active control is still to expensive and unreliable to apply to general cases, at the moment.

Industrial Noise :

Industrial noise comes from either an established factory, or by building works. As industrial noise is much more of a problem to people working in a factory, who might suffer permanent hearing damage as a result of noise, than to the general public, who report annoyance at it. Because of this most of the engineering solutions and regulations governing factory noise are to deal with the high levels inside, though this does have a benefit outside the factory.

There are however, specific guidelines that the government has developed, under the guidance of engineers, to estimate the number of people likely to be affected by an industrial noise. With this tool, engineers can plan factories so they will disturb as few possible in the surrounding area. Once again the benefits of a new factory have to be weighed against the disturbance to the local inhabitants, and if necessary, offer some compensation to those effected.

Ocean Noise :

The ocean has always been a noisy place to live. Breaking waves cause lots of noise, shrimps click their claws, surf on the beach and various fishy noises all contribute to the general hubbub. Now however, the greater amount of shipping has dramatically increased the noise in the ocean, drowning out all the natural noises. Huge engines hammer away, driving the ships across the oceans, radiating sound from their propellers and through their hulls.

Through all this clamour there is one creature that really relies on hearing quiet noises across vast distances, and that creature is the whale. Whale song has been popular for several years now, but the whales have been using it much longer than that. It is widely believed that the whales use their song to communicate with each other, across hundreds of miles of ocean. With the increase in noise in the ocean people are beginning to worry that the whales won't be able to hear each other, and so will be less likely to find each other. This could effect their migration patterns, and so effect their population.

As always it comes down to the engineer to improve on what has gone before. The ship owners don't want to pay a fortune to make their ships quiet for the benefit of a few fish (I know they're mammals really), so combined with government legislation, the engineers make ships that are cheaper, faster, and more efficient, while still making less noise than older ships. This keeps both the ship owners and environmentalists happy, while allowing the whales to sing in peace.