Aircraft Noise and Child Development: An Environmental Health Risk Assessment

Aircraft Noise and Child Development: An

Environmental Health Risk Assessment

NSCEH Student Project Nov 2005

The Identified Issue• Has aircraft noise affected, or likely to affect, the

cognitive development of children, in a school of 200, located under the flight path?

• If yes, what is the level of risk and what recommendations can be provided to the school population and authorities?

• Airport due for expansion• Recent school academic results indicated a six month delay

compared to state average• Parents extremely concerned about test scores, and the

potential impact of aircraft environmental noise on their children’s reading skills, attention, memory, thinking

ability and general health • Risk Assessment undertaken by local scientists in consultation with school, PTA and authorities

Process Undertaken• Hazard Identification

– Noise health effects & researched evidence

• Dose Response– Response of children to noise levels

• Exposure Assessment– Means and level of exposure by the children

• Risk Characterisation– Integration of information to assess risk; explanation of

confounders, uncertainties & limitations

• Risk Management & Communication– Recommendations & communication plan

HAZARD IDENTIFICATION

Aircraft Noise - affecting children's cognitive performance?

Adverse effect of noise…….?

WHO DEFINITION:“a change in the morphology and physiology of an organism

that results in”:

• Impaired functional capacity, or• Impaired capacity to compensate for additional stress, or • Increase in susceptibility of an organism to the harmful

effects of other environmental influences.

This definition includes any temporary or long-term lowering of the physical, psychological or social functioning of humans or human organs.”

Health Effects from Noise

• Hearing • Annoyance

• Sleep disturbance

• Stress / Hormonal

• Cardiovascular effect

• Communication

• Auditory discrimination

• Speech perception

• Sense of well-being

• Concentration

• Impairs cognitive performance

• Reduces task performance

• Diminishes memory

• Motivation

Comparative noise levelsQuiet conversation 50 – 60dB(A)

Vacuum Cleaner 70dB(A)

Aircraft 87 – 100dB(A)

Take Off / Landing

MP3 Headphones 94dB(A)

Rock Band 120 – 150dB(A)

85dB(A)

Noise - Health Effects on Children

• Vulnerable group @ 5 – 11 years– Critical stage in cognitive development. – Less coping mechanisms for additional stressors– Reading and language acquisition – complex cognitive tasks

• Physiological and Psychological Effects

• Noise affects the ability to perform complex cognitive tasks due to:– Communication - auditory discrimination & speech perception– Distraction – sustained attention, memory and recall– Fatigue – sleep disturbance

“reading, attention, problem solving and memory are most strongly affected by noise” (WHO)

Evidence – related studies

• Los Angeles Airport Study (Cohen et al, 1980, 1981)

• New York Airport City (Evans & Maxwell, 1997)

• Munich Airport Study (Evans et al, 1995; 1998)

• Heathrow Studies (Haines et al, 2001 a,b,c; 2002)

“Over 20 studies have reported that noise adversely affects children’s academic performance”

Stansfield S (2004), ‘Review on state of the art in children and noise”, 3rd International Conference on Children’s Health and the Environment, Centre for Psychiatry, Queen Mary University of London

DOSE RESPONSE

Aircraft Noise - affecting children's cognitive performance?

Dose-response

Noise location dBLAeq16hr, 6am-10pm

Outside 50-55

Inside 35

Table 1: Noise levels in a classroom below which health effects would not be expected

Source: Berglund et al (1999)

Source: Stansfeld et al (2005)

Relationship of Test Scores to Noise

Source: Hygge, Evans and Bullinger (2002)

Comparison of Test Scores pre/post Airport Closure (ie:Noise Removal)

• “Stimuli context effect”– Impact of noise range, duration and time

between noise– Annoyance with noise greater when exposed

to loud noise intermittently, lesser when noise constant.

– (Aasvneg and Engdahl, 1999)

• Aircraft noise levels above 50 dB(A) in a classroom can affect performance

EXPOSURE ASSESSMENT

Aircraft Noise - affecting children's cognitive performance?

Exposure Assessment• Exposure route is auditory

• Disruption caused by aircraft is a key factor in this issue

• Health effects above 70db(A)

• Range : between 85.7 - 100.8 dB(A)

Model representing noise effects

noise exposure

speech perception

impaired reading

predictor mechanism outcome

• Exposure measured using noise loggers, questionnaires, tape recordings

– NB: Loggers require calibration, so data interpretation may also be influenced by position and other environmental noises (traffic, wind, playground)

RISK CHARACTERISATION

Aircraft Noise - affecting children's cognitive performance?

• Average number of flights/day = 19.5 (1/hr)• Aircraft noise impact ~ 15 sec/flight

Relationship between Aircraft Noise Exposure Forecast (ANEF) Level

and Community Reaction in

Residential Areas

(National Acoustic Laboratories Report No 88)

• Increased air traffic has potential to adversely affect reading results, anxiety levels, affecting children, parents, school staff and other local population

• Potential costs associated with long-term noise exposure include:– remedial education, – decreased cognitive development – decreased attention – health costs

Potential Costs

Risk Uncertainty

Assumptions: • All flights pass over the school

Risk Assessment Limitations:• Interpretation of noise data-contribution affected by noise logger location, and other noise sources• Questionnaires highly subjective• Data from one school (200 pupils) – no control

• Climate - wind, humidity etc affect sound transmission in the air

Risk Uncertainty Confounding Factors:

• Unknown other factors include:

– socio-demographics,

– excess noise in home setting,

– other chemical/biological factors (eg: Pb),

– children’s hyperactivity / developmental disability,

– teacher quality

• Other sources of environmental noise at the school include road traffic, other classrooms

• Flight paths are affected by wind direction

RISK MANAGEMENT

Aircraft Noise - affecting children's cognitive performance?

Evidence Findings• Sufficient evidence indicates that noise has a

negative effect on cognitive performance.

• However, it is uncertain whether the current school performance can be directly attributed to aircraft noise:

– Existence of confounding factors and data limitations

– A lack of control studies in the local situation and lack of evidence about prior test results

– Insufficient evidence on effects of combined noise (WHO)

• Risk management is recommended to address relevant standards

Site Plan of St Stephens SchoolM

ain

Sou

th

Roa

d

Henley Beach Road

Wes

t W

ing

South Wing

North Wing

Hall

90dBA

Noise Control RecommendationsExisting Noise Measurements

100dBA

90dBA

AS2021-2000 Table 3.3 Design Noise Level = 50dBA

Noise Level MeasurementsDuring Aircraft FlyoverSouth Wing: 90dBANorth Wing: 90dBAWest Wing: 90dBAHall: 95dBA

Noise Levels while Semi-Trailer on South RoadSouth : 75dBANorth : 75dBAWest: 85dBAHall: 65dBA

Noise Control Recommendations

100dBA

50dBA90dBA

Noise Control Data and SolutionControl Description ANR

dBA$ Responsibility

Ceiling Insulation

High Density Insulation Batts laid on existing ceiling

30 $15/m2 School & PTA

Roof Insulation

Acoustic frame consisting of insulation and battens

30 $25/m2 Commonwealth Government Grant

Double Glazed Windows and Doors

Additional windows added to create double glazing, or replace existing windows and doors.

35 $150/ unit

Commonwealth Government Grant

Screen Wall

Single brick wall 115mm Thick rendered one side.

45 $100/m School & PTA

Risk Management &

Communication• Formation of an ad hoc group involving EPA,

Health, AAL, Commonwealth Government, and school representatives.

• Further monitoring to be co-ordinated by this group throughout the remediation process

• Proposed communication strategy– Letter to parents informing them of school information session

– Notice of information evening to be advertised in community media

– School information session to explain situation and future plans

– Parents to receive regular updates on remediation status of school

– Fact sheet to be made available to media

Questions?

Team:

Alison Jones, Xiao Liu

Colin Marsh, Lester Nation

Graham Ohmsen, Louise Miller-Frost, Barry Mortimer

Peter Collins, Kirsten

Supported by:

Hannah Aumann and A/Prof Dino Pisaniello