Health effect-based noise assessment methods: a review and feasibilty study.

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.