Definition:• It is any unwanted, disturbing or harmful sound thatimpairs or interferes with hearing, causes stress,hinders concentration and work efficiency, or causesaccidents.• It can also be defined as displeasing human ormachine created sound that disrupts the activity orhappiness of human or animal life.
• The sensation of loudness is related to the intensity ofthe energy carried by the sound waves and ismeasured in units of decibels (dB).• Sound pressure becomes damaging at about 85 dBand painful at around 120 dB. At 180 dB it can kill.• Human ears can take sound up to about60dB without damage or hearing loss.
Sources of noise pollution:The source of most noise worldwide is1. Transportation systems, motor vehicle noise, but also including aircraftnoise and rail noise.2. Poor urban planning may give rise to noise pollution, since side-by-sideindustrial and residential buildings can result in noise pollution in theresidential area.3. Office equipment, factory machinery, construction work, appliances,power tools, lighting hum and audio entertainment systems.• The sound of an automobile is about 70 dB; the sound of a jet aircrafttaking off, about 120dB; sound level in the interior of a home is about45 dB. So, prolonged exposure to sound levels above 85dB can causepermanent hearing damage.• Noise in the range of 50-60 dB is sufficient to interfere with sleep,producing a feeling of fatigue upon awakening.
Human health effects:1. Noise disturbs sleep2. Can damage physiological and psychological health3. Can cause annoyance and aggression, hypertension, high stress levels,tinnitus, hearing loss, and other harmful effects4. Tinnitus (ringing or buzzing in the ear) can lead to forgetfulness, severedepression and at times panic attacks.5. Chronic exposure to noise may cause noise-induced hearing loss.6. High noise levels can contribute to cardiovascular effects.7. Rise in blood pressure8. Noise poses a danger to childrens development [low birth weights andfetal defects, such as cleft palate]9. Blood is thickened by excessive noise. Eosinophilia, hyperglycaemia,hypokalaemia and hypoglycaemia are caused by alteration in the blooddue to noise.
Environmental effects:1. Can have a detrimental effect on animals by causing stress,increasing risk of mortality by changing the delicatebalance in predator/prey detection and avoidance.2. Interfering with animals use of sounds in communicationespecially in relation to reproduction and in navigation.3. Can lead to temporary or permanent loss of hearing toanimals.4. Very loud noise may affect plant growth indirectly becauseit produces vibrations that shake the plants.
Environmental effects of noise depends on:1. Total energy2. Sounds pitch3. Frequency4. Time pattern and,5. Length of exposure to the sound.
How can we reduce noise pollution:1. Ear Protection2. Modifying noisy activities and devices3. Shielding noisy devices or processes4. Shielding workers or other persons from the noise5. Moving noisy operations or machinery away frompeople6. Using anti-noise (a technology that cancels out onenoise with another).7. Use of noise barriers8. Limitation of vehicle speeds,9. Limitation of heavy duty vehicles
10. Use of traffic controls that smooth vehicle flow to reducebraking and acceleration11. Aircraft noise can be reduced to some extent by design ofquieter jet engines,12. Redesign of industrial equipment, shock mountingassemblies and physical barriers in the workplace.13. Research now shows that plants can also help to reducebackground noise levels inside buildings by up to 5 decibels14. Interior plants can absorb, diffract or reflect backgroundnoise in buildings, thereby making the environment morecomfortable for the occupants [especially plants with lots ofsmall leaves]15. Law enforcements.
Learning to protect yourself from NoisePollution:1. Always wear hearing protection when workingaround loud noises2. Take breaks when working in noisy areas3. Limit exposure to loud music4. Have regular hearing tests for any loss of hearing5. keep indoor plants
Noise levels of common soundsPain 130 dB120 dBAircraft taking off 110 dBLoud Rock Music 100 dBSemi Truck (short term hazard) 90 dBJack Hammer 80 dBTraffic (ocupational limit) 70 dBConversation 60 dBBackground office noise 50 dBWindmill 40 dB30 dBQuiet bedroom 20 dB10 dBThreshold of hearing 0 dB