Some information about noise pollution
What is noise pollution?
Noise pollution can be defined as any unwanted or offensive sounds that unreasonably intrude into and disturb our daily lives. It seems to be an inescapable part of modern urban life.
http://en.wikipedia.org/wiki/Noise_pollution
http://science.org.au/nova/072/072sit.htm
What are the impacts of noise pollution?
Noise pollution impacts on our general environment and has a negative and objectionable effect on the places where we live, work and recreate. It diminishes the value of our property or requires us to spend money on dealing with it (purchasing sound proofing measures).
But it is not just noise pollution’s impact on our environment. Of greater concern is the effect excessive noise can have on the physical and psychological well-being of people. Although it is difficult to quantify the effects it has on human health, excessive noise has been shown to cause hearing problems, stress, poor concentration, productivity losses in the workplace, communication difficulties, fatigue from lack of sleep, and a loss of psychological well-being.
At its most extreme, loud noise can cause instant and permanent hearing loss. Normal hearing depends on the three components of the human ear: the outer, middle and inner ear. The inner ear or cochlea is the most susceptible to damage by loud noises. It contains thousands of tiny hair cells that transmit sound impulses to the auditory nerve. Explosive sounds with peak noise levels of 140 dB or more can destroy these cells and cause permanent deafness. Extended exposure to loud noise can lead to long-term hearing loss.
Excessive noise not only contributes to hearing loss, it also affects human health in many other ways. Research has shown that people exposed to noise pollution on a continuing basis have a higher incidence of headaches, take more sleeping pills and sedatives, are more prone to minor accidents, and are more likely to seek psychiatric treatment.
Exposure to high noise pollution levels has also been shown to lead to a range of physical symptoms such as accelerated heartbeat, high blood pressure, gastro-intestinal problems and chronic fatigue. Some of these problems are relatively easy to treat medically, but other psychological effects such as insomnia, nervousness, anxiety and depression can be longer lasting.
http://www.faqs.org/health-encyc/The-Environment-and-Health/The-Environment-and-Health-Effects-of-sound-on-the-eardrum.html
For a comprehensive statement of the impact of excessive noise on health read the World Health Organisation report "Guidelines for Community Noise" at http://www.who.int/docstore/peh/noise/guidelines2.html
How is noise measured?
The intensity of sound (the level of noise) is measured is measured by sound level meters and expressed in unit called decibels (dB), which describe the relative intensity of a sound based on a logarithmic scale containing values ranging from 0 to 194.
Although a zero value on the decibel scale represents the weakest sound audible to humans and sound intensity increases in correspondence with numeric values, the relationship among the values on the decibel scale is not linear but algorithmic. Therefore, the simple assumption that a sound with a 50 dB level is twice as intense as a sound with a 25 dB level would be incorrect. Rather each three decibel increments in the scale indicates an approximately 50% change in sound pressure (or noise) levels. Thus, a 3 dB increase means sound levels have increased by about 50%. If a car that emits a noise level of 77 decibels (a very noisy car) is modified to produce a noise of 80 decibels, that would indicate that its noise levels would be 50% higher than previously. So, while 77 to 80 dB may not seem like a big change, it would be half as much again increase in audible sound.
Some sound sources measured in decibels (dB)
- Jet aircraft, 50 m distance 140 dB
- Threshold of pain 130 dB
- Threshold of discomfort 120 dB
- Chainsaw, 1 m distance 110 dB
- Disco, 1 m from speaker 100 dB
- Diesel truck, 10 m distance 90 dB
- Kerbside of busy road, 5 m distance 80 dB
- Vacuum cleaner, distance 1 m distance 70 dB
- Conversational speech, 1 m distance 60 dB
- Average home 50 dB
- Quiet library 40 dB
- Quiet bedroom at night 30 dB
- Background in TV studio 20 dB
- Rustling leaves in the distance 10 dB
- Threshold of hearing 0
So, who is responsible for controlling noise pollution?
We Australians are becoming increasingly irritated by unwanted noise. Thousands of complaints are made to authorities every year. (In Sydney there are over 100,000 noise complaints made to authorities annually.) There has also been a sharp increase in noise litigation, with people prepared to take legal action to protect their peace and quiet. But who is responsible for taking action?
No single government authority in Australia has overall responsibility for controlling or reducing noise pollution. Frankly, it is a mess of overlapping and inadequate roles and responsibilities. For example:
- The Commonwealth Government is responsible for controlling aircraft noise and noise emission standards for new motor vehicles.
- A State Government environment protection agency in each state regulates environmental noise in its state.
- The National Occupational Health and Safety Commission has a national code of practice that provides advice on management of noise in the workplace.
- Municipal councils have local laws that deal with neighbourhood and recreational noise issues
- The police in each state are often called in to deal with noise problems.