Noise pollution
Overview
This particular pollution is ever increasing with due to the rise in the utilization of heavy duty machineries of industrial facilities and vehicles, synonymous to the increase in the standard of living in most countries. We make sounds practically every seconds of our day, but to the extend it has reached an unfavorable high intensity which had cause many disturbances and irritation to others emotionally that has adverse effects on our daily activities.
Noise levels can be measured by decibel method:
Decibel - one tenth of a bel where one bel represents a difference in level between two intensities I1, I0 where one is ten times greater than the other. Thus, the intensity level is the comparison of one intensity to another and may be expressed:
Intensity level = 10 log10 (I1/I0) (dB)
For instance, the difference between intensities of 10-8 watts/m2 and 10-4 watts/m2, an actual difference of 10,000 units, can be expressed as a difference of 4 bels or 40 decibels.
These are the few examples of threshold decibels of noises made:
| Threshold of hearing |
0 dB |
Motorcycle (30 feet |
88 dB |
| Rustling leaves |
20 dB |
Food blender (3 feet) |
90 dB |
| Quiet whisper (3 feet) |
30 dB |
Subway (inside) |
94 dB |
| Quiet home |
40 dB |
Diesel truck (30 feet) |
100 dB |
| Quiet street |
50 dB |
Power mower (3 feet) |
107 dB |
| Normal conversation |
60 dB |
Pneumatic riveter (3 feet) |
115 dB |
| Inside car |
70 dB |
Chainsaw (3 feet) |
117 dB |
| Loud singing (3 feet) |
75 dB |
Amplified Rock and Roll (6 feet) |
120 dB |
| Automobile (25 feet) |
80 dB |
Jet plane (100 feet) |
130 dB |
Other noise measurement systems are:
- community noise equivalent level
- composite noise rating
- equivalent energy level
- noise and number index
- noise exposure forecast
- noise criterion
- noise level
- noise pollution level
- noise rating
- perceived noise level
- traffic noise index
- sound level
- sound level meter
- sound pressure level
- world soundscape project
Sources and Methods
We can classify major sources that lead to noise pollution to the following categories:
- Road traffic noise
- Air traffic
- Rail traffic
- Neighborhood and domestic noise
- Incompatible land use
- Industrial noises
Source: http://library.thinkquest.org/C0111040/Types/types.php
The impacts of noise pollution
- The impacts of noise in Greater Johannesburg are greatly affected by the nature of the topography and the large amount of high rise buildings in the area, which reflect noise back and forth across the landscape. The climate of the region also affects noise pollution as the temperature inversions experienced during winter reflect noise back towards the ground (Walmsley, 1997).
If sound waves consist of regular vibrations it is often judged to be pleasing, whereas random wave forms are experienced as noise. Excessive noise results in hearing becoming dull and decreased hearing sensitivity. This effect is at first temporary and should the person remain in a quiet environment their hearing soon recovers. Exposure to very loud noise or repeated exposure to more moderate noise may result in permanent hearing loss. Induced hearing loss can be prevented but can never be cured. The danger is that a person may not perceive the noise to be a problem, but may already have experienced hearing loss.
Noise can create a stress response in humans, affecting the endocrine, nervous, digestive, and cardiovascular systems. Adaptation and habituation can occur, but prolonged exposure may lead to any of the diseases of adaptation, including digestive and cardiovascular problems (Veitch, 1995).
- Noise that affects feelings and reactions has a psychological effect on humans. This normally occurs at noise levels that do not cause a physical effect. Annoyance, stress and hypertension are symptoms of the psychological impacts of noise pollution.
- Communication
Noise levels interfere dramatically with communication that may often lead to a loss in productivity.
Tiredness and headache can often be traced back to exposure to continuous unpleasant noise levels.
This can result in tiredness, headaches, reduced productivity, and in severe cases can result in prolonged hearing loss. The effect however is related to factors such as the loudness, pitch, predictability, and controllability of the noise as well as the age, gender and exposure duration of the person affected (Veitch, 1995).
- Traffic
The existence of noise at potentially harmful levels has been documented as resulting from automobiles and buses, from rail traffic and from aircraft. Transportation noise is particularly disturbing because it is ever present in large urban areas; it is uncontrollable, loud and unpredictable. Ambient noise levels in apartments near rail systems can reach the 80 to 100 dB range, and noise levels near freeways in third floor apartments have been recorded at 90dB.
According to Veitch, the general impact of noise includes headaches, irritability, insomnia, the reduction in sexual desire and loss of appetite. Veitch concluded that this trend has been present during the past 20 years. Veitch (1995) highlighted the following studies as proof of the impact of community noise.
| Study |
Results |
| Ward & Suedfeld, 1973 |
Tension, uncertainty and faster talking |
| Damon, 1977 |
Greater arrest rate, decreased likelihood of caring for the area’s surroundings |
| Appleyard & Lintell, 1972 |
Decrease in informal interaction amongst neighbours |
| Cohen, Evant, Krantz, & Stokols, 1980 |
Poor scholastic performance |
| Cohen, et al. 1980 |
Elevated blood pressure |
| Veitch, 1996 |
60% of 18-19yr olds show a noise-induced hearing loss |
| Further, Ayres and Hughes, 1986 |
Impairment of visual acuity by the presence of loud music |
| Thiessen, 1988 |
Negligible impact on sleep |
http://ceroi.net/reports/johannesburg/csoe/html/nonjava/Pollution/Noise/impact.htm
Noise pollution control
Insulation
Vegetation
- absorption and screening of noise pollution in housing area and cities, adopting the 'green city' concept.
Zoning
- restructuring of urban areas to maintain a separation between residential areas and zones of excessive noise
- systematic coordination of development in an industrialized area to ensure proper zoning of factories from buildings nearby
- sustainable development of industries proportion to an area to ensure equilibrium with population in that area in order to produce a balanced physiology and psychology of its inhabitants
Source: http://library.thinkquest.org/C0111040/Types/types.php |
