Nicole D Porter and Bernard F Berry
Centre for Mechanical and Acoustical Metrology
National Physical Laboratory
Teddington
MiddlesexIan H Flindell
Institute of Sound and Vibration Research
University of Southampton
Southampton
HampshireABSTRACT
The UK Department of Environment (DETR) requested the National Physical Laboratory (NPL) together with the Institute of Sound and Vibration Research (ISVR), to review noise standards used for assessing the health impact of environmental noise. The aim of this work was to advise the DETR of the extent to which it is justifiable to use existing knowledge on potential health effects to define future noise standards and targets. The literature confirms that there are a number of potential effects of noise on health, although the evidence in support of actual health effects other than those based on reported bother or annoyance and on some indicators of sleep disturbance is quite weak. Although the scientific evidence suggests thresholds below which it is unlikely that there is an impact on health, we cannot interpret these as definitive at this time. Existing standards and regulations usually take the results of primary research into account to some extent, but social, political and historic factors are at least as important. The 1995 WHO guideline criteria are interpreted as a precautionary approach to setting criteria.
It is concluded that given the present state of knowledge, it would be unwise to base future environmental noise standards and regulations on what are at present hypothesised non-auditory health effects until future research can make the present confused situation clearer. An increased emphasis on non-auditory health effects, as opposed to annoyance, as the outcome variable may lead to greater transparency in the development of standards, although there is considerable doubt as to the magnitude of these effects. To ensure that non-auditory health effects are included in future standards, research is required. This must be carefully designed, not only in terms of its planning and execution, but also in terms of setting precisely defined and achievable objectives.
© Crown Copyright 1998
Reproduced by permission of the Controller of HMSO
ISSN 1369-6785
National Physical Laboratory
Teddington, Middlesex, United Kingdom, TW11 0LWNo extracts from this report may be report may be reproduced without prior consent from the Managing Director, National Physical Laboratory; the source must be acknowledged.
Approved on behalf of the Managing Director, NPL,
by Dr G R Torr, Director, Centre for Mechanical and Acoustical MetrologyEXECUTIVE SUMMARY
1. The UK Department of Environment (DETR) have recognised that in considering future policy on environmental noise, the idea of standards with a close link to health effects should be explored together with a consideration of the implications. It is within this framework that DETR placed a contract with the National Physical Laboratory (NPL), in collaboration with the Institute of Sound and Vibration Research (ISVR), to review noise standards used for assessing the health impact of environmental noise. The aim of this work was to advise the DETR of the extent to which it is justifiable to use existing knowledge on potential health effects to define future noise standards and targets. This report describes the study and its findings.
2. The main objectives of this work were to (1) consider existing information on health effects in order to establish noise levels at which there may be particular effects on the population, and from this, (2) advise on the feasibility of establishing effects-based standards which could be used to inform the setting of objectives and targets.
3. The work itself was conducted in two phases: the phase 1 review of the effects of environmental noise, current standards and noise criteria/limits and the interpretation of 1995 WHO Community Noise Guidelines document; and the phase 2 feasibility study.
4. The results are reported in five main sections: an examination of the scientific evidence for health effects due to noise, an investigation of the practical noise criteria used to assess environmental noise, a guide to the interpretation of the WHO guidelines, conclusions on whether effect based assessment methods can be established and issues for DETR to consider in setting out the way ahead.
5. The concept of noise and health is examined in general terms in section 3. There are a number of definitions and defined requirements for (good) health but it is concluded that descriptors that can be used to assess the impact of noise on health and can provide a framework on which to base a method to balance costs and benefits are the most useful to the decision maker.
6. The literature confirms that there are a number of potential effects of noise on health, although the evidence in support of actual health effects other than those based on reported bother or annoyance and on some indicators of sleep disturbance is quite weak. In fact the available literature on this topic is contradictory. In general, it is only the most poorly designed and executed studies which show significant effects. There are serious methodological difficulties involved in being able to carry out definitive research. This also means that significant effects amongst the most susceptible members of the population remain scientifically plausible, even if unproven.
7. On examining existing information on dose-response relationships based on scientific evidence, we can make some conclusions from the primary research. However it is found that since the evidence in support of potential health effects other than annoyance is weak, we cannot at present define meaningful exposure-response relationships for other effects. Non-acoustic factors are also important in determining a response and serve to add variability to the data. Although the scientific evidence suggests thresholds below which it is unlikely that there is an impact on health, we cannot interpret these as definitive at this time.
8. The general link between an effect and its impact on health is even more complex, and depends on many aspects including how one effect can modify another, the role of other modifiers and confounding variables, the number of effects, cumulative noise exposures, the susceptibility of individuals and the risk factors associated with multi-origin health conditions.
9. Section 4 looks at the actual practical setting of existing criteria and targets as opposed to criteria based solely on primary scientific research evidence. Practical noise targets are a compromise between the desirable and the affordable. The desirable relates to the thresholds suggested by the scientific evidence below which no effect is expected. The affordable involves weighing the costs and benefits in monetary and social costs. Practical noise limits are usually based above these lower desirable thresholds.
10. On reviewing environmental noise regulations and standards in the UK and in other EU countries, we find that existing standards and regulations usually take the results of primary research into account to some extent, but social, political and historic factors are at least as important. It is very important to be clear about the role played by these factors in the aetiology of current standards and regulations.
11. In view of the uncertainties involved in setting standards, there are moves within Europe to adopt a precautionary approach when setting future noise standards and regulations to protect against possible health effects. An example of this is the 1995 WHO guideline document which is reviewed in section 5. While this precautionary approach may be justified by the scientific plausibility of these effects, it is necessary to place these possible effects in proper perspective. An over-precautionary approach to setting future noise standards and regulations might lead to unacceptable impacts in other areas.
12. In section 7 it is concluded that given the present state of knowledge, it would be unwise to base future environmental noise standards and regulations on what are at present hypothesised non-auditory health effects until future research can make the present confused situation clearer.
13. There could be greater transparency in the way in which future standards and regulations are developed so that the public can become more aware of both the strengths and limitations of these standards. An increased emphasis on non-auditory health effects, as opposed to annoyance, as the outcome variable may lead to this greater transparency, although there is considerable doubt at the time of writing as to the magnitude of these effects due to environmental noise. Non-auditory health effects cannot be included in the development of future standards without further research. On the other hand, further research will be unlikely to yield definitive results unless it is very carefully designed, not only in terms of its planning and execution, but also in terms of setting precisely defined and achievable objectives.
[ Previous ] [ Contents ] [ Next ]
Published 12 September 2000
Noise Index
Environmental Protection Index
Defra Home Page