Exposure-effect relationships between road traffic and aircraft noise exposure and reading

comprehension: The RANCH Project.

www.ranchproject.org

C Clark, R Martin, E van Kempen, H Davies, M M Haines, J Head, I Lopez-Barrio, M Matheson, S Stansfeld.

Queen Mary, University of London, UKUniversity of Stockholm, Sweden

CSIC Madrid, SpainRIVM, Bilthoven NetherlandsGöteborg University, Sweden

– 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)

Aircraft, road traffic & rail noise - the international studies

Over twenty studies have reported that noise adversely affects children’s academic

performance

• Effects demonstrated for aircraft and road traffic noise

• Effects not always demonstrated after adjustment for socioeconomic status

• Effects may be reversible - Munich Study

• Mechanisms:

– Restrict attention to central cues

– Reduce learning motivation

Noise Exposure & Reading Comprehension - the international studies

Gaps at the start of RANCHGaps at the start of RANCH

•No exposure-effect relationships for noise and children’s health and cognition

•Fewer studies of the effects of road traffic noise

•No knowledge about the effect of combined noise

exposure

•No comparison of effect size across countries

•Noise guideline values based on health effects for

adults were proposed for children. A child evidence

base was required

Objectives of the RANCH projectObjectives of the RANCH project •To provide knowledge on exposure-effect relationships between chronic exposure to noise at school and children’s cognition and health

- for aircraft noise

- for road traffic noise

- for combinations of aircraft and road traffic noise

•To provide knowledge on–the total impact of the sound environment –the relationship between road traffic noise and children’s sleep

•To provide guidelines for a pan-European policy taking advantage of the cross-border environmental diversity of four European countries

Heathrow airport, London, United Kingdom

Schiphol airport, Amsterdam, the Netherlands

Barajas airport, Madrid, Spain

•Common methodology between countries

•Examine exposure-effect relationships in 9-10 year old children between chronic exposure to noise at school and

•cognitive function

•health

•noise annoyance

Airport Field Studies

School Selection Protocol

• Selection of study area, identification of primary

schools

• Exclusion of non-state schools

• Schools matched within countries for socioeconomic

status and main language spoken

School Noise PredictionAircraft Noise

• Based on 16 hour outdoor LAeq contours

Road Traffic Noise

• In the NL, provided by modelled data using the EMPARA model

• In the UK & Spain, based on proximity to roads and traffic flow

- data confirmed by on-site noise measurements

• Noise surveys at 4m distance from facade of main school

entrance (exclusion of schools with insulation or other

dominant noise source)

Noise Exposure Bandings

Road

Aircraft

R4

R3

R2

R1

A4

A3

A2

A1

71dB

32 dB

30 dB

77dB

2 schools selected per cell based on SES matching and noise

prediction

Reading Comprehension

- Assessed using nationally standardised tests in each

country.

• UK - Suffolk Reading Scale (Hagley, 2002)

• Spain - ECL-2 (de la Cruz, 1999)

• NL - CITO Readability Index (Staphorsius, 1994)

Socioeconomic Variables

-Assessed in questionnaires completed by the child and

parent.

Measures

Procedure

• Children aged 9-10 years

• No children excluded from selected classes

• Written consent from parents and children

• Classroom based testing with careful monitoring

• Standardised test procedures and instructions

• Acute noise measurement during testing

Sociodemographic Outcomes• age

• gender

• employment status

• crowding

• home ownership

• mother’s educational attainment

• long standing illness

• main language

• classroom glazing

• parental support for school work

Same measures achieved across all three countries

Participation rates

63%90%27920Spain

86%89%33730Netherlands

78%89%291182UK

ParentResponse Rate

Child Response Rate

No of schools

No ofchildren

Data pooled and analysed using multilevel modelling

Relationship between aircraft noise exposure and reading comprehension

B = change in outcome score associated with 1db change in noise

NB: Multi-level Models adjusted for centre, age, gender, employment status, crowding, home ownership, mother’s education, long standing illness, main language and parental support.

Aircraft Noise B SE ConfidenceInterval (95% )

p value from χ 2

Pooled estimate -.009 .003 -.015 to -.003 .001

UK -.010 .004 -.018 to -.002

NL -.004 .006 -.016 to .008

Spain -.009 .004 -.017 to -.001

Exposure-Effect relationship for Aircraft Noise Exposure and Reading

Comprehension

-.2

0.2

.4R

eadi

ng Z

-sco

re

30 35 40 45 50 55 60 65 70aircraft noise dB(A)

Reading age was delayed by up to 2 months in the UK and

1 month in the NL for a 5dB change in noise exposure

Adjusted for age, gender and country

Relationship between road traffic noise exposure and reading comprehension

B = change in outcome score associated with 1db change in noise

NB: Multi-level Models adjusted for centre, age, gender, employment status, crowding, home ownership, mother’s education, long standing illness, main language and parental support.

Road traffic noise B SE ConfidenceInterval (95% )

p value from χ 2

Pooled estimate .002 .003 -.004 to .008 .445

UK -.002 .005 -.012 to .008

NL .003 .005 -.007 to .013

Spain .011 .007 -.003 to .025

Exposure-Effect relationship for Road Traffic Noise Exposure and Reading

Comprehension

-.6

-.4

-.2

0.2

.4R

eadi

ng Z

-sco

re

30 35 40 45 50 55 60 65 70road traffic noise dB(A)

Adjusted for age, gender and country

Discussion

• Inverse, linear relationship between aircraft noise exposure

and reading comprehension in all three countries

• This relationship could not be accounted for by

socioeconomic variables nor acute noise.

• Confirms the influence of chronic aircraft noise exposure on

reading comprehension.

Why an effect for aircraft noise and not road traffic noise?

• No relationship between road traffic noise and reading

comprehension in all three countries

• However, we cannot rule out an effect of road traffic noise at

higher levels - > 71dB

• Aircraft noise = greater intensity - high short term levels

• Road traffic noise = more constant

Conclusions

• Similar effects of noise on reading performance across Spain, the Netherlands and the United Kingdom

• Action is recommended at a European level to provide healthy educational environments for children attending high noise exposed schools

• Noise exposure should be considered with other environmental aspects in the school planning process

Some remaining questions

Long-term exposure

Do impairments diminish if children are removed from noisy

environments or increase if children remain in noisy

environments?

Intervention

Does sound insulation have ameliorative effect on impairments in

cognitive performance?

Mechanisms

What role do classroom acoustics and noise interference in

teacher communication play in the causation of noise effects?