1. Environmental Noise and Health: The Latest Evidence
Professor Deepak Prasher
Institute of Laryngology and Otology
University College London

2. Day and Night Noise Levels
Typical Noise Level LeqdBA
Day Night Acoustical Quality
natural sounds only
quiet rural environment
suburban neighbourhood
urban noise situation
very noisy, unfit for
permanent habitation

3. Noise Level and Effect
<55dBA Desirable level outdoor Suburban neighbourhood
55-65dBA Urban “Grey Areas”: Annoyance
>65dBA Black spots:
Stress effects, sleep disturbance, communication performance deficits
>75dBA Unfit for Human habitation,
hearing loss, cardiovascular effects

4. European City Noise Desirable Indoor Comfort Leq <65dBA
New Residential Areas outdoor levels <55dBA
Urban “Grey Areas” Levels 55-65dBA
Black Spots Levels >65dBA
Large European Cities:Number of People
exposed to high levels 3 times national average
Percentage living in “grey areas” increasing
(OECD 1991)

5. Noise Levels in Environment
Normal Conversation 45-55dBA
Car 50km/h dBA
HGV 50km/h dBA
Motorcycle 50km/h dBA
Train 200km/h dBA pk
Discotheque(Leq) dBA
Jet (Take off,100m) dBA
Military low level flights dBA

6. Speech Communication in Noise
Socially people talk at 2-4m distance: Noise should not exceed 55-60dBA
Outdoor recreation people talk at 5-10m: Noise levels should not exceed 45-55dBA
At work people can converse at 1m with difficulty with noise at 78dBA.
For prolonged conversations noise level must be lower than 78dBA at work

7. Hazardous Noise Levels
Level Hazardous if communication not possible when in the sound
Tinnitus (ringing in ears) after sound exposure
Sounds muffled after leaving sound exposure area

8. Noise Environment in Europe
450million (65%) exposed to >55dBA
113 million (17%) exposed to >65dBA
9.7million (1.4%) exposed to >75dBA
No systematic differences across Europe
Eastern European Cities noisier than Western
Data poor from Central and Eastern Europe

9. Costs of Noise to Society
Estimate: 0.2 to 2% GDP
0.2% equates to 12Billion Euros annually

10. Noise Sources in Europe
Road Traffic
Air Traffic
Rail Traffic
Industry
Recreational Activities
Construction Sites
Traffic on Waterways

11. Auditory Effects Acoustic Trauma: Sudden hearing damage
Tinnitus: Ringing in the Ears
TTS:Temporary threshold shift
PTS: Permanent threshold shift
Interference with Communication

12. Non-Auditory Effects Annoyance Sleep Disturbance Attention Motivation
Stress reactions
Cardiovascular problems
Endocrine problems

13. Annoyance Noise is annoying
Generally the louder the noise the greater the annoyance
But there are non-acoustic factors affecting annoyance
Degree of annoyance not directly related to adverse health effects

14. Annoyance from Street Noise
West Germany (UBA 1988)
Inhabitants Percentage Annoyed
<
5-20,
20-100,
>100,
Annoyance increases with increase in Population

15. Factors affecting Annoyance
Primary Acoustic: Sound level, frequency and duration
Secondary Acoustic: Spectral complexity, fluctuations in frequency, level, localisation of noise source
Non-acoustic: Adaptation and past experience, listener’s activity interference, predictability of noise, individual personality

16. Noise and Sleep Increases time taken to fall asleep
Causes awakenings and changes in sleep stages; reduces REM and slow wave sleep
Sleep disturbance in turn may lead to poor performance and change in modd next day
Noise sensitive individuals and elderly more vulnerable
Chronic exposure leads increase of cortisol
Adaptation possible but not complete habituation

17. Noise and Sleep
In Europe 10-26% ( m) : Severe difficulties falling asleep or staying asleep
Chronic Sleep disorders lead to loss of efficiency, psychological well being, learning in childhood, social interaction and driving ability
Drivers falling asleep cause 20% of accidents on German Roads

18. Noise and Performance
Distracting effects of Noise impair performance especially in children, noise sensitive and anxious people
Type and degree of control important in degradation of performance
Learning in Schools impaired due to outdoor and/or indoor noise levels
Memory: Recall impaired in children

19. Noise and Hormones
Prolonged exposure to stress leads to immune dysfunction and increased vulnerability to disease
Environmental stress leads to production of stress-related hormones
Hypothalamus-pituitary-adrenal (HPA) axis plays a crucial role in this
Cortisol is closely associated with stress related health problems

20. Noise and Hormones Noise can affect the HPA function
Salivary cortisol enhanced during mental work under 90dBA noise and NOT under quiet conditions
Circadian decline in cortisol NOT seen in chronically exposed workers to noise >85dBA but did with use of headphones
Noise exposure during gestation leads to enhance HPA responses to stressors in later life

21. Noise and Cardiovascular Effects
Acute noise effects: increase in heart rate, blood pressure and peripheral vasoconstriction
Heart rate changes to noise during sleep do not habituate
No epidemiological evidence of relationship between noise exposure and blood pressure in adults BUT consistently seen in children
Increased risk of ischaemic heart disease with outdoor levels >65-70dba
Association shown between noise and serum lipids in women and young men

22. Noise and Mental Health
Community based Studies show high levels of environmental noise associated with depression and anxiety
Aircraft noise in children impairs quality of life but no depression or anxiety

23. Noise and Fatigue
Increased fatigue and irritability after work in noisy environments
Fatigue and headache more common among noise exposed workers in a survey of 50,000 workers
Reaction times prolonged after one week in high noise levels increasing gradually compared to controls which improved

24. Noise and Children
Aircraft noise : Difficulties in attention, communication, learning and memory
Concentration, motivation and language acquisition affected by increased outdoor and/or indoor noise levels
Raised blood pressure seen with prolonged noise exposure to traffic noise

25. Leisure Noise Risk to hearing and tinnitus from:
Loud music : Concerts, discotheques, Personal cassette players
Noisy toys, arcade and computer games
Sports activities and venues
DIY activities

26. Social Noise induced hearing impairment
Audiometric thresholds may be within normal limits but impairment may be present
Inability to decipher speech in noisy conditions
Tinnitus: An early warning signal?
Early onset of presbycusis?

27. Loud Music and Hearing
Percentage of young people reporting dulled hearing and/or tinnitus
Rock Concerts ( dBA) %
Night Clubs ( dBA) %
Personal Stereos( dBA) 17%

28. Strategies EC 5th Environmental Action Programme
No Person should be exposed to noise levels which endanger health and quality of life
Exposure to 65dBA night Leq should be phased out
At no time should a level of 85dBA be exceeded
No increase in level for those affected by 55-65dBA

29. These groups may constitute 30% of Population
Special Groups
Children
Elderly
Sick People
Hearing Impaired People
These groups may constitute 30% of Population

30. Noise measures and Health
Noise measures based only on energy summation NOT sufficient to :
characterize noise environments
health effects
or predict health outcome
Noise fluctuations, number of noise events and inclusion of low frequency components is important