Night noise guidelines for Europe - WHO/Europe - World Health ...

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EXECUTIVE SUMMARY
PROCESS OF DEVELOPING GUIDELINES
In 2003, the WHO Regional Office for Europe set up a working group of experts to
provide scientific advice to the European Commission and to its Member States for
the development of future legislation and policy action in the area of control and surveillance
of night noise exposure. The review of available scientific evidence on the
health effects of night noise was carried out by an interdisciplinary team who set out
to derive health-based guideline values. The contributions from the experts were
reviewed by the team and integrated into draft reports following discussion at four
technical meetings of the working group. In 2006, all the draft reports were compiled
into a draft document on guidelines for exposure to noise at night, which was
reviewed and commented on by a number of stakeholders and experts.
At the final conference in Bonn, Germany, on 14 December 2006, representatives
from the working group and stakeholders from industry, government and nongovernmental
organizations reviewed the contents of the draft document chapter by
chapter, discussed several fundamental issues and reached general agreement on the
guideline values and related texts to be presented as conclusions of the final WHO
Night noise guidelines for Europe.
NOISE INDICATORS
From the scientific point of view the best criterion for choosing a noise indicator is its
ability to predict an effect. Therefore, for different health end points, different indicators
could be chosen. Long-term effects such as cardiovascular disorders are more
correlated with indicators summarizing the acoustic situation over a long time period,
such as yearly average of night noise level outside at the facade (L night,outside ) 1 ,
while instantaneous effects such as sleep disturbance are better with the maximum
level per event (L Amax ), such as passage of a lorry, aeroplane or train.
From a practical point of view, indicators should be easy to explain to the public so
that they can be understood intuitively. Indicators should be consistent with existing
practices in the legislation to enable quick and easy application and enforcement.
L night,outside , adopted by the END, is an indicator of choice for both scientific and
practical use. Among currently used indicators for regulatory purposes, L Aeq (Aweighted
equivalent sound pressure level) and L Amax are useful to predict short-term
or instantaneous health effects.
SLEEP TIME
Time use studies, such as that undertaken by the Centre for Time Use Research,
2006 (www.timeuse.org/access/), show that the average time adult people are in bed
is around 7.5 hours, so the real average sleeping time is somewhat shorter. Due to
personal factors like age and genetic make-up there is considerable variation in sleeping
time and in beginning and end times. For these reasons, a fixed interval of 8
hours is a minimal choice for night protection.
Though results vary from one country to another, data show (see Fig. 2 as an example)
that an 8-hour interval protects around 50% of the population and that it would
take a period of 10 hours to protect 80%. On Sundays, sleeping time is consistently
1 hour longer, probably due to people recovering from sleep debt incurred during the
week. It should also be borne in mind that (young) children have longer sleeping
times.
1 L night is defined in the END as the outside level. In order to avoid any doubt, the suffix “outside” is added in
this document.