The harmful effects of noise include increased annoyance, mental tension, irritability and I emotional disturbance at work and at home. Greater circulatory, heart and equilibrium problems were found in textile workers exposed to very noisy environments. The most pervasive and dangerous harm from noise hazard is the permanent incurable deafness as a result of continued exposure to noise levels above 90 dB.
The annoyance of sound is the most general problem now-a-days. Various noise level groups and their corresponding impact on affected person are given. Since harmful effects of noise on the body increases with duration and intensity of noise, hence, noise levels should not exceed the limits.
(i) Auditory Effects: These include auditory fatigue and deafness. Auditory fatigue appears in the 90 dB and may be associated with side effects as whistling and buzzing in ears. Deafness can be caused due to continuous noise exposure. Temporary deafness occurs at 4000-6000 hz. Permanent loss of hearing occurs at 100 dB. Mumbai and Kolkata are the nosiest cities in the world. Many persons have risk of deafness.
(ii) Speech Interference:
ADVERTISEMENTS:
High background noise level affect the efficiency of offices, schools and other places where communication is of vital importance. External sounds can also interfere with conversation and use of the telephone, as well as the enjoyment of radio and TV. The maximum acceptable level of noise under such conditions is 55 dB. Background level of 70 dB is considered very noisy.
(iii) Sleep Interference:
The loss of sleep from noise affects personal well-being and job performance. The preferable level is below 40 dB. Frequent sleep interference is a health hazard, since it deprives a person of the restorative process for his organs to renew their supply of energy and nutritive elements provided by a good night’s sleep.
(vi) Behavioral Effects:
ADVERTISEMENTS:
Noise pollution lowers down the hearing capabilities of an individual, in turn, results in poor attention and concentration, nervousness etc.
(iv) General Annoyance:
General annoyance is felt at about 75 to 85 dB. Balanced persons express great annoyance at even low level of noise as crowded, highway, radio etc. Blood vessels get constricted, breathing rate is affected and muscle tension changes.
(v) Loss of Working Efficiency:
ADVERTISEMENTS:
Many people complain that noise makes them mentally ill and reduces their working efficiency. Irregular bursts of noise are more disruptive than steady noises and sound levels of 90dB may interfere with the performance of a task.
(vii) Emotional and Personal Logical Effects:
It is observed that people suffering from hypertension, isomania, fatigue, blood pressure and deafness show symptoms of living in noise polluted areas. Continuous exposure to high noise level is likely to cause stable reactions in the individuals and thus disturbing his personality make up.
(viii) Acoustical Privacy:
ADVERTISEMENTS:
Noise pollution leads to lack of acoustical privacy. People living in multi-storey building built with lightweight construction materials have frequently experienced lack of acoustical privacy.
(ix) Pathological Effects:
High frequencies sound above the normal audible range (Ultrasonic sound, whose frequency is above 20,000 Hz) can affect the semi-circular canals of the inner ear and make one suffer from, excessive fatigue, and headaches vomiting.
On the other hand, low frequency sound below the normal audible range (Infra-sound, whose frequency is less than 16 Hz) can cause dizziness, nervous fatigue, nausea and loss of balance, at higher intensities, infrasound can produce resonance in the internal body organs of a person giving the effects of reduced heart beat, variations in blood pressure, breathing difficulties and possibly death.
ADVERTISEMENTS:
(x) Other Effects:
It has been observed that there are increased incidences of birth defects, still births and unusually low weight among children born to mothers living near high noise producing sources, such as airports, blasts sites etc.