Effects of noise

1. EFFECTS OF NOISE
Noise
• All sounds that are distracting, annoying, or harmful to everyday activities such as work,
rest, entertainment, study and so forth are regarded as noises. In fact, any sound judged by
the recipient as undesirable can be considered as a noise.
• Noise health effects are the health consequences of elevated sound levels.
• Elevated workplace or other noise can cause hearing impairment, hypertension, ischemic
heart disease, annoyance, and sleep disturbance.
• Changes in the immune system and birth defects have been attributed to noise exposure.
• Although some presbycusis may occur naturally with age, in many developed nations the
cumulative impact of noise is sufficient to impair the hearing of a large fraction of the
population over the course of a lifetime.
• Noise exposure also has been known to induce tinnitus, hypertension, vasoconstriction,
and other cardiovascular adverse effects.
• Beyond these effects, elevated noise levels can create stress, increase workplace accident
rates, as well as stimulating aggression and other anti-social behaviours.
• The most significant causes are vehicle and aircraft noise, prolonged exposure to loud
music, and industrial noise.
• Firecrackers may upset domestic and wild animals or noise-traumatized individuals.
• The most common noise-traumatized persons are those exposed to military conflicts, but
often loud groups of people can trigger complaints and other behaviours about noise.
• One in five Europeans is regularly exposed to sound levels at night that could significantly
damage health.
• Noise also is a threat to marine and terrestrial ecosystems.
Effects of noise
• Age-related (presbycusis)
• Hearing loss
• Cardio-vascular effects
• Stress
• Annoyance
• Child physical development
• Cognitive development
• Whether or not a sound is undesired by a person will depend on a number of factors, e.g.
Loudness, Frequency, Continuity, Variation with time, Time of occurrence, Information
content, Origin of the sound, Recipient's state of mind and temperament, Background noise
level.
Generally, the effects of noises are:
Hearing Loss: Exposure to high noise levels causes hearing loss. This loss of hearing may
be temporary, permanent, or a combination of both. Temporary hearing loss, also called
Temporary Threshold Shift (TTS), results from exposure to short-term loud noises. As time
passes, temporary hearing loss will disappear. However, if the human ear is not given the
opportunity to recover, permanent hearing loss or Permanent Threshold Shift (PTS) will
result because of the destruction of parts of the ear. Permanent hearing losses cannot be
treated.

2. Other Health Effects: People living or working in noisy environments develop the habit
of shouting; some are stressed and become irritable. There is evidence that noise can lead
to psychiatric disorders. When human beings are exposed to high noise levels, the blood
vessels constrict and muscles tense.
Speech Interference & masking
• One cannot effectively use speech communication in an environment in which the
background noise level is too high. Sometimes, the masking of warning shouts by
background noise is responsible for industrial accidents.
• Nevertheless, a reasonable level of background noise is sometimes useful, e.g.
(i) the masking of speech so that speech privacy in large areas is maintained.
(ii) minimizing the effect of intruding noises.
(iii) maintaining the sanity of human beings: human beings cannot tolerate absolute
silence in a perfect soundproof environment for any length of time.
Effects of Noise on wildlife
• Hearing impairment and loss
• Disturbance and stress
• Psychological suffering
Noise Permissible Exposure Limits (PEL)
• Utilize administrative or engineering controls when sound levels exceed Noise
Permissible Exposure Levels e.g. 8 hours permitted duration per workday for 90 dB
sound level.
• Provide hearing protectors if above controls fail to reduce sound levels within Permissible
Exposure Levels.
• Impulsive or impact noise should not exceed 140 dB.
Control
SOURCE PATH RECEIVER
•Controlling or attenuating at its source
•Controlling or attenuating along its path
•Controlling or attenuating at the receiver
Noise Control
• Administrative Control
• Engineering Control
• Personal Protective Equipment (hearing protective devices)
Administrative Controls
• Operate noisy equipment on second or third shifts.
• Rotate employees through high-noise areas.
• Modify existing machinery.
• Place noise limit specs. on new equip.
• Maintain equip. in good condition.
• Use noise control when installed.
• Reporting noisy equip. to supervisor for repair.
Engineering Controls
• Reduce noise at the source.
• Interrupt the noise path.

3. • Reduce reverberation and structural vibration.
Personal Protective Equipment (Hearing Protection Devices - HPD)
• Employers shall provide to employees exposed to 8 hr TWA of 85 dB at no cost.
• Employers shall ensure being worn:
• by employees exposed to 8 hr TWA of 90dB or greater
• by employees exposed to 8 hr TWA of 85dB or greater and:
• Whose baseline audiogram has not been established
• Who have experienced a threshold shift
Hearing Protection Device (HPD) Noise Reduction
• HPD must reduce employee noise exposure below PEL e.g. below 8 hr TWA of 90 dB.
• Employees with standard threshold shift (STS), HPD must reduce employees noise
exposure below an 8 hr TWA of 85 DB.
Noise Control Methods
• Acoustical materials
• Acoustical enclosures and barrier
• Silencers and mufflers
• Reverberation control
• Vibration control
• Louvers
Conclusion
Noise is undesirably connected with our day to day life. It’s a part in our economic growth
. There is no way to get rid of this noise completely from our life . But we can manage to
reduce and restrict them to some extent by following the few measures mentioned above.