Environmental Noise
July 2009 Number 338
ENVIRONMENTAL NOISE
Noise pollution affects quality of life and has been
linked to health problems. The EU Environmental Noise
Box 1. Decibel Scale and Noise Indicators
Directive (END) aims to manage noise and preserve
Meters measure sound pressure on the decibel (dB) scale.
quiet areas by engaging the public, local authorities and
0dB is the threshold of human hearing, 50dB is around the
level of a normal conversation and 120-140dB is the
operators. This POSTnote examines the effects of noise,
threshold of pain. A 3dB increase is equal to a doubling in
the END and practical measures for noise management.
sound pressure but, if the sound is steady, will only just be
noticed by a human. A 10dB increase equates to a doubling
Background
in the perceived loudness. Standards for environmental noise
Environmental noise is unwanted or unpleasant outdoor
use the ‘A-weighted’ decibel scale [dB(A)] which mimics the
sensitivity of the ear to different frequencies.
sound generated by transport and industry. This
POSTnote will not look at neighbourhood noise, which
The environmental noise indicators used vary between
includes burglar alarms, dogs barking and licensed
countries and industries and depending upon the type of
sound that is being measured. They include:
premises, or occupational noise, which is noise
• the maximum sound level reached in a period of time;
experienced in the workplace.
• the average sound level over a period of time. If noisy
events are intermittent, the average value may not
The European Community Green Paper on Future Noise
reflect the actual disruption caused by each event;
Policy (1996) recognised that environmental noise is
• indicators that are weighted to account for sound at
“one of the main local environmental problems in
disruptive times of the day such as evening or night.
Europe” but that it has had a lower priority than other
environmental problems, such as air or water pollution. It
also recognised that, despite significant reductions in the
The Effects of Environmental Noise
noise produced by individual sources, total exposure to
Environmental noise rarely reaches the sound pressure
environmental noise has not changed significantly. For
levels associated with hearing impairment. However,
example, the introduction of quieter vehicles has been
noise can cause annoyance, is commonly blamed for
offset by an increase in traffic.
sleep disturbance and has been linked by researchers to
less obvious effects, such as cardiovascular and mental
Environmental noise in the UK is controlled by numerous
health problems and reduced performance at work or
laws, guidelines and standards covering planning,
school. The ways in which noise affects health are not
transport, the environment and compensation. To provide
clear. A forthcoming report commissioned by the
a common approach to noise management, the European
Department of Health may recommend research areas
Union introduced the Environmental Noise Directive
that could inform future policy.
(END) in 2002. This was transposed into Environmental
Noise Regulations in England and the devolved
Annoyance
administrations in 2006.
Annoyance can cause stress and longer term health
Measuring Sound and Noise
problems such as hypertension (permanently raised
blood pressure). It has been estimated that 55% of the
The decibel scale and various noise indicators are used to
UK population1 live in dwellings where the outdoor
quantify noise exposure levels (see Box 1). However, they
environmental noise level exceeds a guideline value
are not intuitive and can result in difficulties when
suggested by the WHO,2 above which some people
communicating noise levels to the public. A sound’s
become seriously annoyed. On average, annoyance
unpleasantness depends upon its loudness, frequency
increases as the measured sound level increases but,
content, duration, intermittence, predictability and
individual attitudes to the same noise source can vary
source. Individuals find different sounds annoying, so no
due to, for example:
single measure can predict the reactions of everybody.
postnote July 2009 Number 338 Environmental Noise Page 2
• personal factors - including where people are and what
deprived populations experienced slightly higher exposure
they are doing at the time;
to night time noise.6 Poorer people may be less able to
• context - in an urban area people might be more
afford houses in quieter areas. However, some people
accepting of transport noise than in a rural area;
will choose to pay more to live in noisy areas for better
• choice - people who have paid more to live in a quiet
access to amenities.
area may be particularly sensitive to its disruption.
The EU Environmental Noise Directive
The Attitudes to Aviation Noise Sources in England
The END requires Member States to create strategic
(ANASE) study concluded that people were more
noise maps and to generate noise action plans. Noise
annoyed by aircraft noise in 2005 than they were in the
maps indicate the extent of environmental noise due to
1980s,3 although the methodology of the study received
road, rail, aircraft and industry. Action plans identify
some criticism during peer review.
steps to reduce noise where necessary and preserve
Sleep Disturbance
‘Quiet Areas’. Member States should also inform and
consult with the public about noise exposure, its effects
Evidence on the links between noise exposure and sleep
and noise management measures, in line with the UN
quality is complex. The WHO recommends that sound
Aarhus Convention, which promotes citizens’ involvement
levels should be kept below an average level of 30dB(A)
in environmental matters (see POSTnote 256). The first
in the bedroom, or a maximum of 45dB(A) for a single
round of noise mapping covering large urban areas and
event.2 Higher sound levels have been related to reduced
major airports, roads and railways was completed in
quality of sleep and awakenings. It appears that the
2007 and the devolved administrations are now at
majority of people will get used to common background
various stages of action planning.
noises at higher average sound levels and sleep will not
be disturbed. However, the full restorative effects of sleep
may be reduced even if people are not awakened.
Box 2. Noise Modelling
Sound propagation is affected by many factors including the
Cardiovascular Problems
frequency of the sound (lower frequencies travel further), the
Unusually loud noises cause elevated heart rates and
shape and size of barriers, the ground surface (concrete
blood pressure, which quickly return to normal once the
reflects sound while grassland absorbs it) and the weather.
noise stops. The effects of longer term exposure are not
Both the quality of the input data and the calculation
method can affect the accuracy of the model. In England
well understood, but it has been linked to a slightly
there have been fewer data available for road and rail traffic
increased likelihood of hypertension, heart disease and
flow at night to date, meaning that the first set of night time
heart attack. A recent study estimated that road noise
noise maps are less accurate than day time noise maps.
could cause around 100 attacks a year in Greater
A common methodology for computing noise exposure at
London: 1.8% of the total incidence.4 Separating the
airports has been the use of 'average noise contours'. The
effect of noise from other confounding factors, such as air
contours derive from the 'noise profile' of individual aircraft
pollution, body mass index, age and smoking is difficult.
types (the sound pressure at ground level and at a given
distance from the airport) and the flight path of each aircraft,
Performance and Educational Achievement
tracked using radar. Work has been ongoing to ensure
Noise has been shown to affect the performance of adults
common modelling methods are used across the EU. The
and children in cognitive tasks. The EC sponsored
UK Civil Aviation Authority believes that its ANCON model is
accurate to within ±1dB(A). Road and rail noise modelling
RANCH study investigated the link between children’s
is more problematic as objects on the ground can shield
health and noise in the UK, the Netherlands and Spain.5
sound. Guidance in the END was limited and different
It found that chronic exposure to aircraft noise can impair
approaches have been adopted in different countries.
children’s reading comprehension and memory to some
extent. No link was found between road noise and
performance. It was suggested that aircraft noise may be
Noise Mapping
more disruptive than road noise due to its “variability and
The noise maps required by the END indicate the
unpredictability”. However, previous studies at higher
average noise exposure level that would be experienced
noise exposure levels had found a link between road
outside a building.7 They have been produced by
noise and performance.
computer modelling (Box 2), as the cost of directly
measuring sound levels nationwide render it impractical.
Vulnerable Groups
The modelling of sound propagation is complex and it is
Certain groups of people are more vulnerable to
unlikely that the calculated average exposure levels will
environmental noise. High background noise levels make
always reflect local attitudes to noise.
conversation more difficult for the hearing impaired.
Studies have linked a range of psychological symptoms
The purpose of noise maps is to aid prioritisation of
to environmental noise, including anxiety, stress,
action and to allow comparison of noise levels across
irritability and mood change. There is no evidence that
Europe. Different approaches have been adopted by EU
noise directly causes mental illness, but research
countries so levels cannot yet be fairly compared.
suggests that people who are prone to certain psychiatric
Choosing a common methodology is difficult as not all
disorders may be more sensitive to environmental noise.
countries have the same quality of input data. Repeated
mapping will allow trends to be identified. Noise maps
The European Federation for Transport and Environment
are considered to be sufficiently accurate near major
(T&E) believes that environmental noise unfairly affects
noise sources to allow the areas of highest exposure to be
poorer people. A study in Birmingham found that socially
identified for Noise Action Plans.
postnote July 2009 Number 338 Environmental Noise Page 3
Noise Action Plans
administrations suggests a number of possible noise
The Department for the Environment, Food & Rural
management measures but leaves identification of the
Affairs (Defra) recognises that more clarity is needed on
most appropriate option to the competent authorities.
where the responsibility for noise management lies in
The benefits of implementing noise management should
England. The Highways Agency, Network Rail, airport
be weighed against costs to the wider community. This
operators and planning and environmental health
section describes ways to manage noise.
departments in local authorities will have to co-ordinate
Reduction at Source
to meet the requirements of the END. The competent
Transport noise is caused by movement of the vehicles
authority is required to assess noise maps, decide if the
through the air, contact of wheels with a road or track
predictions are accurate and on what action, if any,
(rolling noise), engine noise and braking. Limits for noise
should be taken.
emissions from new aircraft and road vehicles have been
The END is expected to provide a framework for
tightened progressively. Noise from jet aircraft has
prioritising action and use of available funds through
reduced by 75% since the 1960s.10 New aircraft designs
Noise Action Plans. Local authorities are concerned that
can easily meet the current noise standards and so these
these will be ineffective if they are not incorporated into
provide little incentive to improve further on current
development and local transport plans. In the longer
technology. The main drivers are now local controls (see
term, Defra intends that the action planning process
POSTnote 197).
should help it to draft a Noise Strategy for England,
Noise limits for new road vehicles have been tightened by
which may also be adopted by the other devolved
up to 11dB since the 1970s. Despite this, there has
administrations. A consultation on a national strategy
been no significant decrease in road vehicle noise. This
was held in 2001 but as yet no definite timescales have
has been attributed to:11
been announced.
• limits not being very stringent when originally set;
Quiet Areas
• noise from vehicles in-service not being well
The END requires Member States to identify and aim to
controlled. In the UK an MOT tester is required to
preserve ‘Quiet Areas’ (Box 3). Research has highlighted
judge exhaust noise subjectively;
the importance of access to quiet areas for well-being in
• noise certification tests not reflecting all driving
urban areas.8 Quiet spaces may help reduce annoyance
conditions. Engine noise has reduced but limits have
and stress. A recent survey by Environmental Protection
had little impact on tyre noise, which is now one of
UK found that 91% of people think that it is important to
the dominant sources. EU legislation on quieter road
protect quiet areas from an increase in noise.9
tyres is expected to be published this year;
•
Some noise experts and policy makers are concerned that
vehicles remaining in-service for many years, so that
the full benefit of tightened limits takes time to realise.
the dual objectives of the END - to reduce average noise
exposure and to preserve quiet areas - are not wholly
Guidance for Action Plans encourages steps such as
compatible. For example, aircraft flight paths are often
wider use of quieter road surfaces, traffic flow
designed to avoid densely populated areas. In some
management, continuously welded rails (which eliminate
cases, the only alternative is to fly over quiet areas.
noise as train wheels move over joints) and operational
procedures, such as those adopted around airports (Box
Box 3. Designation of Quiet Areas
4). T&E believe that future revisions of the END should
In the first round of Noise Action Plans, the END requires
include explicit limits for transport noise.
Member States to identify ‘Quiet Areas’ in large urban areas.
Eventually it is expected that Member States may also be
required to designate Quiet Areas in open country.
Box 4. Operational Procedures in Aviation
Operational procedures can affect the aircraft noise
Scotland started with parks and national heritage sites and
experienced by the community surrounding an airport (see
then selected candidate sites based on a set of criteria
POSTnote 197 on Aircraft Noise). One procedure that has
including land type, noise level and area. Wales asked local
been recently introduced is Continuous Descent Approach,
authorities to identify quiet open spaces that are of
where the aircraft descends smoothly rather than in stages.
importance to the local community. Their list includes parks,
While the main benefits are in fuel and CO2 savings, noise
playing fields, allotments and cemeteries, reflecting the fact
on the ground can be reduced by up to 5dB for locations
that many different types of open space may be valued for
between 15-40km from the airport.
their quietness. The suitability of the candidate areas will be
assessed based on factors such as accessibility.
New navigation systems allow aircraft to follow flight paths
with a much higher accuracy than was previously possible.
England and Northern Ireland intend to adopt an approach
This allows airport operators to decide whether to
similar to Wales. The consequences of designating an urban
concentrate noise over a single population or to share it. The
site as a ‘Quiet Area’ and how this fits in with the other
stability of Noise Preferential Routes (NPRs) for aircraft
government policies, such as the aim to deliver greener
arriving at and leaving airports is valued by those looking to
public spaces, are not yet clear.
purchase a house, as it allows them to make informed
decisions. A review of airspace is required to accommodate
new navigation systems and further changes would be
Noise Management
needed for a proposed third runway at Heathrow. Some
Environmental noise is already controlled to some extent
NPRs may have to change. At some airports, operational
by planning guidance, noise nuisance and compensation
restrictions or curfews (bans on night flights) may be
legislation and EU directives on transport noise.
operated, to give local residents periods of relative quiet.
Guidance on Noise Action Plans from the devolved
postnote July 2009 Number 338 Environmental Noise Page 4
Shielding and Insulation
Most large transport operators have a system for handling
Buildings can shield other more noise-sensitive buildings
complaints. Guidance for Noise Action Plans states that
or spaces, such as schools or hospitals, from major noise
Defra will review these systems. Some airport operators
sources. New developments can be laid out to ensure
also liaise with the public on noise issues via local
that each building has one ‘quiet side’ to accommodate
consultative committees, but these have no authority to
noise-sensitive rooms such as bedrooms. In noisy areas,
enforce action. The Department for Transport has
buildings can be built or fitted with noise insulation and
guidelines on their operation. The Aviation Environment
acoustic double glazing.
Federation approves of these guidelines but feels they are
not always put into practice by airport operators.
Noise barriers are structures such as fences or earth
mounds that are built between a noise source, such as a
road or railway, and a building or open space. Their
Box 5. Wind Farms
effectiveness can vary widely, depending upon design. In
Wind farms are often subject to planning delays due to fears
1999, the Highways Agency identified 79 sites where
about potential noise from local residents. Government
guidelines for noise from wind farms reflect the fact that they
there were particularly serious noise issues. An annual
are mostly built in quiet rural areas. Generally, people do not
budget of £5m was ring-fenced for the installation of
experience noise problems, although there have been
noise barriers at these sites. Ten sites still have to be
complaints about noise from wind developments in the UK.
addressed and four new sites have since been identified
Issues can often be resolved by simple steps like limiting the
where noise barriers will be installed during 2009/2010.
turbine’s speed of rotation. Industry worries that lengthy
planning processes and the current guidelines could
Planning
endanger the government’s 2020 renewable energy target
Defra intends that the identification of noise management
for onshore wind.
areas and Quiet Areas will raise the profile of noise issues
among local planning authorities. Planning can be
Overview
effective at addressing the local impact of new
• Environmental noise affects a large proportion of the
developments. Approaches that planning authorities can
population.
take towards managing noise include:
• Individuals can react very differently to the same
• land-use planning to ensure sufficient separation
noise. Some individuals are more likely to be annoyed
between noise sources and noise-sensitive areas;
or to suffer health effects than others.
• conditions for new developments, including
• The EU Environmental Noise Directive aims to manage
sympathetic timing of operations or requirements for
and, where necessary, reduce average noise exposure
shielding or insulation.
levels and to preserve Quiet Areas by engaging the
The planning process gives an opportunity to explain the
public, local authorities and operators.
potential impact of a new development on the local noise
• Noise can be managed by reducing it at source, and
climate and for public consultation on potential
by planning, shielding or insulation, while attitudes
management measures. The Planning Act (2008) aims
can be influenced by effective community liaison.
to make the planning process more efficient, particularly
Endnotes
for large infrastructure projects that will benefit the entire
1 Skinner, C.J. & Grimwood, C. J., Applied Acoustics, vol 66
country (Box 5), but environmental and community
(2005), pp 231-243
groups are concerned that changes will result in less
2 The World Health Organisation, Guidelines for Community Noise,
consultation and in local noise issues being overlooked.
1999
3 DfT, Attitudes to Noise from Aviation Sources in England, 2006
Economic Measures
4 www.london.gov.uk/mayor/strategies/noise/docs/technical-
Economic measures can help to reduce noise:
report2.pdf
• airports can impose additional fees on noisy departing
5 Stansfeld, S.A. et al, The Lancet, vol 365 (2005), pp 1942-1949
and arriving aircraft;
6 Brainard, J.S. et al, Urban Studies, vol 41 (2004), pp 2581-2600
• congestion charging can reduce traffic and noise,
7 noisemapping.defra.gov.uk
although this can be offset by increased traffic speeds;
8 Gidlof-Gunnarsson & Ohrstrom, Landscape and Urban Planning,
•
vol 83 (2004), pp 115-126
the Land Compensation Act (1973) allows
householders exposed to increased noise levels due to
9 Environmental Protection UK, ICM Poll on Transport Noise, 2009
10
new or improved highways or airports to receive
DfT, The Future of Air Transport White Paper, 2003
11 International Institute of Noise Control Engineering, Noise
compensation, either for loss of value to their property
Emissions by Road Vehicles – Effect of Regulations, 2001
or to cover the cost of sound insulation.
12 Omega, Indices to Enhance Understanding & Management of
Public Information and Consultation
Community Responses to Aircraft Noise Exposure, 2009
Noise maps, as specified in the END, show only the
average noise exposure. Other indicators can improve
POST is an office of both Houses of Parliament, charged with providing
independent and balanced analysis of public policy issues that have a basis in
public understanding of potential noise impacts.12
science and technology. POST is grateful to Katy Milne for researching this
Examples include the number of movements that exceed
briefing, to the EPSRC for funding her parliamentary fellowship, and to all
a given sound pressure, the number of hours of respite
contributors and reviewers. For further information on this subject, please contact
the co-author, Dr Martin Griffiths, at POST. Parliamentary Copyright 2009
from noise or, for airports, flight paths and their
distribution.
The Parliamentary Office of Science and Technology, 7 Millbank, London,
SW1P 3JA; Tel: 020 7219 2840; email: post@parliament.uk
www.parliament.uk/parliamentary_offices/post/pubs2009.cfm
