Any sound that is undesirable or unwanted may be defined as noise. Noise is a result of human activity from road vehicles, air traffic and railways, work processes, and personal activities.
Noise may be a particularly unpleasant sound or just a sound in the wrong place at the wrong time. A sound that is pleasant to one person may be noise to another. It depends on the circumstances. Music may be a noise to a person who is disturbed by it because they are trying to sleep, study for an exam, and if it does not suit their taste in music.
When a series of similar impulses follow each other at regular intervals the sound that is produced has a musical quality and is generally more tolerable than sounds with different frequencies and amplitudes and which occur at irregular intervals. In other words the more complex the sound the more likely it will be a noise.
Noise is an environmental stressor and levels are rising. At low levels noise can be annoying; this is the most common effect of noise. Noise can be frustrating and harmful to our wellbeing. People feel resentment from intrusions into their physical privacy, the space for our thoughts and emotions which we have marked out as our own. At higher levels noise can be undesirable because it interferes with hearing and speech and at even higher levels it can damage hearing.
Sound waves can travel in air or water, and hearing occurs when the sound waves stimulate the organs of hearing. Noise can vary according to intensity, frequency, duration, intermittence or continuation. Characteristics like volume, tone, duration and repetition determine if a sound is a problem.
Sound is measured in decibels (dB).
Below 80 to 85 dB is generally considered to be safe, but ongoing low-level noise may be stressful for some individuals. The World Health Organisation’s (WHO) industrial noise exposure limit recommedation is 75 dB. The noise threshold for pain is about 120 dB.
The earliest records of hearing loss from noise are from the Bronze Age. Presumably the working of metals such as bronze and later iron by the earliest metal workers would have been a significant risk to human hearing. Continuous hammering of these metals to create tools and weapons is a very noisy process and contributed to hearing loss.
The introduction of gunpowder from China into Europe and the Middle East about 1250 AD and the industrial revolution in 1800 AD starting in Britain, would have contributed to hearing loss from noise. Factories, the development of coal powered steam engines, oil powered internal combustion engines used in transport and later aircraft, increased noise levels dramatically.
In recent years, complaints to government environment departments about noise have greatly increased. Although this may indicate lower levels of tolerance to noise by people in society, noise levels have in fact been rising. Figures suggest the average volume of sound is doubling every 10 years. We have become desensitised to high levels of noise and are unaware of the damage it is doing to our health and wellbeing.
Significant legislation dealing with noise includes the Noise Abatement Act 1960 (UK). The International Standard Organisation (ISO) is the primary body dealing with noise standards. The International Electro-Technical Commission deals with instrumentation.
What you can do
Write a letter or email to your local council if you find noise a problem. Lobby your government to change noise levels and enforce regular car checkups. Let your airport and government know if aircraft are causing you noise-related distress.
Be considerate to others with regards to your car, home stereo and TV volumes. Restrict noisy outdoor activities to daylight hours. Let neighbours know if you are going to be hosting a party or having work done. Keep your car tuned.
Ear protection is important to prevent deafness. Be aware of noise levels and wear the appropriate protection. Use accurate sound level meters to measure sound levels.
Write a letter or email to the editor of your local newspaper; urge him or her to publish your concerns about noise pollution issues.