noise pollution

• What is noise pollution?


  Sound that is unwanted because it is disturbing or causing damage

  -> impacts wildlife and human quality of life
• decibel scale

  -Logarithmic scale

  -1 bel = 10 decibels
• Young persons hearing range

  -20 to 20,000 Hz

  This ranged decreases with age
• sources of noise pollution

  Aircraft noise, railway noise, road traffic noise, industrial noise, domestic noise
• effects of noise on nonliving objects


  Acoustic fatigue

  Vibration damage

  Shock impacts
• Acoustic fatigue


  Some objects have a frequency at which they will naturally resonate if exposed to sound at the frequency

  -Can cause stress and lead to the object eroding
• Vibration damage


  Repetitive vibrations can cause structural damage to buildings, underground pipes and bridges
• Shock impacts

  Force from a sudden very loud sound can damage structures ‘sonic boom’
• Effects of noise on humans

  -Hearing damage

  -Stress related health problems

  -Behavioural changes

  -Communication problems
• Effects of noise on other organisms


  Livestock in injuries

  -loud noises can cause stress and panic, especially to pregnant animals and breeding birds

  -But the thing to establish their territories or attract mates may have difficulties in loud noise areas

  Echo location

  -Animals that rely on full location may not be able to find food

  -Hearing damage and behavioural changes
• Noise pollution controls

  Controlling aircraft noise

  -Planned flight paths

  -airport not around busy areas

  -Strict flight times (7am-

  11pm)

  Airport designer location

  -Away from major population

  -acoustic insulation fitted to buildings affected by noise (double glazing, baffle mounds)

  Engine designs to reduce noise admissions

  -High bypass to ratio engines

  -chevron nozzles

  Airport operations

  -Flightpath planning

  -Constant descent angle

  -Noisy aircraft ban

  -Fines for excessive noise
• Control of railway noise


  Polishing track to avoid wheel vibration

  Sound absorbing suspensions to avoid engine noise
• Control of road traffic noise

  Sound absorbing acoustic fencing to avoid will vibration or tyre noise

  Acoustic insulation to avoid engine noise
• Control of industrial noise

  Air compressors- silencer, air protection

  Use less noisy machines

  Use baffle mains to absorb sound