Calling noise a nuisance is like calling smog an inconvenience. Noise must be considered a hazard to the health of people everywhere. ― William H. Stewart (former U.S. Surgeon General)Generically, the term 'noise' refers to any unwanted sound. It maybe the sound produced when you hammer a nail into the wall, the sound of an aircraft flying over your house, someone playing loud music, or just a baby crying. In short, anything that is not pleasant to your ears. Noise pollution, also referred to as the environmental noise, is defined as displeasing sound created by humans, animals, or machines, which has the tendency to disrupt the environmental balance.
The sources of noise pollution are broadly categorized into two groups: indoor sources, which include loud music, sound of electrical appliances, etc., and outdoor sources, i.e., the noise created by vehicles and industrial machinery. Of these, the outdoor sources of noise pollution easily outdo their indoor counterparts. Similarly, urban areas record more noise pollution as compared to rural areas; the reasons for which are pretty obvious. In 1999, the U.S. Census Bureau revealed that people rated neighborhood noise as the biggest problem they face. Since then, things have turned from bad to worse. No wonder noise pollution is often cited as one of the hazards of urbanization.
Sound pressure, as we hear it, is measured in decibels (dB) using a sound level meter (a.k.a. sound meter). If you are having a normal conversation, the sound meter will show a reading of 60 dB. If you shout, the meter may show a reading in the range of 80 dB. In contrast, a whisper will reflect on the sound meter in the form of 30 dB and rustling of dry leaves in the form of 20 dB. The sound of a lawn mower, MP3 player, air horn, certain musical instruments, motorbike or snowmobile, etc., will go well beyond 85 dB. It's important to stress on 85 dB here, because the Occupational Safety and Health Administration (OSHA) clearly states that exposure to sounds of 85 dB or more―for more than eight hours a day―can lead to noise-induced hearing loss.
Common sources of sound and their decibel levels.
An important thing that you need to make a note of, is that decibels are measured on a logarithmic scale, which means that each 10 dB increase is actually a tenfold increase in the intensity of the sound. Similarly, you also need to understand that the duration for which you are exposed to said source of noise pollution also matters. At 100 dB, the full volume of your MP3 player is no match for the loud sound of a jet plane during the take off―a whopping 120 dB on the sound level meter―and yet, the chances of this music player affecting your hearing far exceed that of the jet plane.
Noise is not just annoying, but is also hazardous to our health. Its health hazards can be categorized into physiological (like hearing loss, hypertension, disturbance in sleep patterns, etc.) and psychological problems (such as annoyance, aggression, and stress). While our ears start paining when subjected to noise of around 130 dB, which is referred to as the threshold of pain, noise of around 85 dB in itself is harmful to our ears, especially in the case of chronic exposure. Like we said earlier, long-term exposure to noise levels over 85 dB can result in a range of health problems, most obvious being the damage caused to the eardrums and resultant hearing loss.
The harmful effects of noise pollution are not just restricted to humans. Even animals have to bear the brunt of the same. The increase in the noise levels beyond a certain extent hampers the process of communication in animals, thus resulting in disturbance in their various life processes. While female frogs are finding it difficult to locate males from their calls, nocturnal species, like owls and bats, are having a tough time locating their prey. In oceans, the noise attributed to commercial shipping and off-shore drilling adds to the stress levels of marine species, like dolphins and whales, as a result of which they end up beaching themselves.
The laws to curb environmental noise either stress on general prohibition on making noise, or specific guidelines to curb the same. In some places, for instance, making noise is completely prohibited, while in other places, it is prohibited for a specific time of the day (from 10 PM to 6 AM), or only to a particular level as far as its intensity is concerned. In the United States, noise emission measures and noise emission standards are monitored under the Noise Control Act (1972). Several ordinances in the United States are based on the Portland Noise Code written by Dr. Paul Herman in 1975.
So the onus is on us citizens to take a note of all the hazards of noise pollution and ensure that we don't contribute to the same. As far as the solutions are concerned, options like noise barriers and limitations on the speed of vehicles are perfect, but only when they are implemented strictly at the ground level.