This year has seen the publication of two discussion papers, both claiming that a national noise strategy is essential to ensure living spaces remain tranquil and quiet. Stephen Grime disagrees, and gives his own analysis of the past 30 years of noise research to explain why

A national noise strategy is only necessary if there are demonstrable problems occurring not only at the local level but also on a macro scale. It is hoped here to demonstrate that not only is such a strategy unnecessary, but also that the arguments on which it would need to be based cannot be sustained using the available evidence. The UK response to noise is based on "statutory nuisance"; noise materially affecting the use and enjoyment of property, loosely described as affecting the average man on the Clapham omnibus. Unfortunately the "average man" does not exist and neither does the concept of annoyance. The legislation looks at what causes annoyance to 50 per cent of a population, using this as the controlling factor for the decision-making process. This legislative process assumes that the noise dose response model used is linear and it can be shown that the model holds true in all reasonable contexts.

From the available evidence it can be shown that three major areas need to be addressed and the meaning and context of use standardised. The concepts that must be agreed before a noise policy is formulated are:
1. The definition of annoyance.
2. The concept of a deteriorating noise climate and
3. The use of numbers of complaints as an indicator of a changing noise climate.

Definition of annoyance
Researchers have reviewed some definitions of noise annoyance which have been used explicitly or implicitly in major field and laboratory studies in different countries.(10)
In some studies annoyance is seen as the outcome of noise disturbances, in other cases it is seen as an indication of the degree of helplessness with respect to the noise source. Researchers from different countries agree on the main components of the annoyance concept, but differing weights are put on each of the components. This could be due to differing concepts of annoyance or due to inconsistent connotations of the related words in the various languages. Annoyance then can be a condition that exists thus causing a person to respond to noise. Equally it can arise as a response that grows from a situation. Regional differences in perceptions will also lead to differing definitions that will also confuse the issues.(12)

For over 60 years researchers have been looking at noise and human response to the problems it causes. The dose-response model has produced a plethora of descriptors, eg LAeq, sone, phon and LDN. Each one of these noise indices has one thing in common, they only hold true for the particular context in which they were created. The reliance on a noise dose-response model in isolation cannot therefore provide a consistent answer that accurately describes noise annoyance problems. If, then, a dose-response model is inadequate to describe noise annoyance, other models need to be explored. Weinstein demonstrates that a person's disposition to complain may be related to irritations in the environment.(16) Zimmer and Ellermeier build on these characteristics.(19) They conclude that noise sensitivity is a stable psychological and not physical personality trait.

There were however, only weak relationships between self-reported measures of noise sensitivity and objective performance decrements under noise. Is it then that people who complain have a higher sensitivity? Do we know they have this trait because they are prone to complain? Zimmer and Ellermeier may be saying nothing other than some people are more sensitive to noise than others. Many researchers have sought to explain noise annoyance in terms of exposure and/or dose.(2,7,11) One concept that stands out in this early research is that scalar responses are defined, but only for community response and not for individual response. Every EHO investigating noise complaints knows that complainants are not necessarily those who live closest to the noise source. If the noise dose-response model or the community response model were to hold true ,then the majority of complainants must live close to and preferably adjacent to the noise source.

Latterly, research has sought to explain some of the discrepancies by the use of psychological methodologies. Some researchers are still concerned with the quantification of an annoyance scale, but accept that annoyance has physical and psychological factors which can influence outcome.(1) The scales are however still community responses. Others, while concerned principally with the formulation of a scalar response to pollution, state: "...there is no close correspondence between objective levels and human reactions. Noise level, for example, is a surprisingly poor predictor of individual dissatisfaction, accounting for only 10-25 per cent of the variance in annoyance."(6) Correlation between noise and annoyance increases when group values are used. The models appear to work for populations, but are much less of a predictor at the individual level. Cheifetz and Borsky's research demonstrates that even when people of differing sensitivities to noise were exposed to the same noise, external to their homes, the major factor in their attitude to noise was the noise generated within their own homes.(3) Staples examines the problems surrounding the formulation of policies based on "mathematical models based on group response". He concludes that policies will need to be informed by a scientific understanding of the psychological and social factors that determine when noise results in annoyance and when noise may affect health as an environmental stressor.

Deteriorating noise climate
Concern is being voiced by the NSCA National Noise Committee that "...in contrast to other pollutants, noise is universal in our urban areas and increasingly encroaching on rural 'tranquil' areas, progressively eroding the period of nighttime quiet."(13) What evidence is this assumption based on? Evidence is available that will show that over a full decade the noise climate in Birmingham has increased by less than 2dB. The NSCA in its own annual survey bases its findings on the perceptions of the information provider, usually local authority environmental health departments. There is also the underlying assumption that a creeping noise background is undesirable. In direct reanalysis of over 57,000 interviews, Fields shows that residents' reactions to an audible environmental noise (a target noise) are only slightly or not at all reduced by the presence of another noise source (ambient noise) in residential environments.8 With considerable variation from survey to survey, Fields states that the best direct estimate is that approximately a 20dB increase in ambient noise exposure (95 per cent confidence interval of 15 - 20 dB) has no more impact than approximately a 1dB decrease in target noise exposure.

Glass and Singer look at the behavioural and psycho-physiological aspects of noise, Rosen the physiological functions and Weiss the environmental and social stressors.(9,14,17) All conclude that these stressors increase the psycho-physiological symptoms in a person. When this stress results in perceived helplessness and vulnerability it in turn increases the likelihood of that person to complain of noise or other environmental nuisance. In these situations noise is seen by complainants as the final factor which takes them to the complaining stage. Without these other social stressors, Weiss also shows that repeated exposure to a noise source will result in diminished adverse reactions.

The right to complain
The evidence linking noise annoyance and noise dose is, if the above is to be believed, contradictory. If then, annoyance cannot be used as predictor of an increasing noise climate then equally an increasing noise climate cannot be used to predict annoyance. Is it possible therefore to use the increasing number of noise complaints recorded as an indicator of an increasing noise problem? Over the past decade the CIEH has collected returns from local authorities. These have indicated that the number of noise complaints have risen year on year.(4) Even when normalised for the past five years, the figures show a consistent rise in the number of complaints.(5)

What must be remembered though, is that throughout this period the public perceptions of the noise policies used by local authorities has changed dramatically. Over this same period central government has produced policies, which changed the local population from receivers of services into customers. Enforcement policies have been published, with local authorities even receiving accolades for doing this well. Charter Marks, quality standards and best value have all served to increase the "customer's" awareness - not only of what the local authority can provide, but of what the customer can expect. Empowerment is now the phrase that the state, through its localised institutions, has pushed to the front of everyone's consciousness. This change is taking place not only in local authorities but also in other publicly funded services, the NHS being another such body in flux.

These changes have been brought forward as a means of ensuring that service providers are accountable to their service users. Pacifism is no longer an acceptable state for service providers or service receivers. All parties must be aware of the changes in policy and act accordingly. After the last war it is said that everybody knew everybody and it is this that controlled some aspects of community life. Ostracisation of digressors was a powerful tool that nobody within a closed community could ignore. It is however the demise of these controls within the community that has in part led to the increasing numbers of noise complaints against those who would in the past have been considered close neighbours.

Young and Willmott stress the importance of family in the community.(18) The family, extended as well as the nuclear, is not separate but an integral part of the community that surrounds it. Long residence in an area was an important part in the formation of the sense of community. The 1960s saw the start of an era of mobility. Social mobility, in addition to job mobility, placed strains on the community.

Full employment saw young people with money. Influences from outside the family suddenly took on more importance. The "swinging sixties" were the start of a cultural revolution. This era also saw the start of a campaign to introduce noise legislation. The Noise Abatement Act 1968 came and was then superseded by the Control of Pollution Act 1974. Evidence of an increasing noise climate or of changing attitudes towards the individual's rights?

Conclusions
Increasing noise complaints may be an indicator that noise levels are increasing, and the numbers of complaints reflect the annoyance felt. Equally, noise levels may be relatively static and it may be just the expectations of complainants that have altered. This may be from their own changing circumstances or changes from within their environment.

With such evidence it is clear that key ideas are described in different ways. It is essential that these differences are resolved so that the evidence from various areas can be compared. Evidence, not only that the noise climate is increasing, but also that this increase is detrimental, injurious or leading to increased complaints must be explored. Without the necessary base data being available, the production of a national noise strategy as a means of controlling the noise climate could be both premature and lead to control measures and responses that may be damaging to the relationships between government and the population.

A national noise policy may be the outcome once the necessary definitions have been agreed and the evidence assembled. At the present time it is too early for a strategy detailing structures, noise levels and methodologies for an ill-defined problem. At present all that can be stated with any certainty is that noise complaints are increasing. It is not, however, increasing noise levels that are the immediate problem.

A Congress plenary session on the arguments surrounding a national noise strategy will be held on 13 September, with speakers from the CIEH and the NSCA.

References
1. Berglund, et al. "Measurement and control of annoyance". In H.S. Koelega (ed.), Environmental Annoyance: Characterization, Measurement, and Control. Amsterdam: Elsevier Science Publishers (1987).
2. Bowsher, et al. "A further experiment on judging the noisiness of aircraft in flight", Acoustica, (17), 245 - 266 (1966).
3. Cheifetz, P., and Borsky, P.N. "Laboratory study of effects of acoustic and non-acoustic variables on annoyance with aircraft noise". In J.V. Tobias, et al (eds.), Noise as a Public Health Problem. Rockville, Maryland: American Speech-Language-Hearing Association (1980).
4. CIEH Noise complaints and prosecutions. www.cieh.org.uk/resources/stats/noise98.htm
5. CIEH Environmental health analysis of five year trends 1993/4 - 1997/8. www.cieh.org.uk/resources/stats/analysis/index.htm
6. Evans, G.W., and Tafalla, R. "Measurement of environmental annoyance". In H.S. Koelega (ed.), Environmental Annoyance: Characterization, Measurement, and Control. Amsterdam: Elsevier Science Publishers (1987).
7. Fidell, et al. "Statistical analyses of urban noise", Noise Control Engineering, (16) (1981).
8. Fields, J. "Reactions to environmental noise in an ambient noise context in residential areas", Journal of the Acoustical Society of America, 104 (4) (1998).
9. Glass, D.C., and Singer, J.E. (1972). Urban stress: Experiments on noise and social stressors. Academic Press.
10. Guski, et al. "The concept of noise annoyance: How international experts see it", Journal of Sound and Vibration, 223 (4) (1999).
11. Hall, et al. "Direct comparison of community response to road traffic and to aircraft noise", Journal of the Acoustical Society of America, (70), 1690 - 1698 (1981).
12. Jonnson, et al. Annoyance reactions to traffic noise in Italy and Sweden. Stockholm: Karolinski Institution & University of Forran (1968).
13. NSCA National Noise Committee, "Towards a noise strategy for the UK". Clean Air, 30 (3) (2000).
14. Rosen, S. "Noise, hearing and cardiovascular function". In Physcological Effects of Noise. New York: Plenium Press (1970).
15. Staples, S. "Public policy and environmental noise: Modeling exposure or understanding effects", American Journal of Public Health, 87 (12) (1997).
16. Weinstein, N.D. "Individual differences in critical tendences and noise annoyance", Journal of Sound and Vibration, (68), (1980).
17. Weiss, L.J. Acute and chronic stress: The mediating effects of loss of control (learned helplessness). Uniformed Services University of Health Sciences (1997).
18. Young, M., and Willmott, P. Family and Kinship in East London. London: Penguin Books (1957).
19. Zimmer, K., and Ellermeier, W. "Psychometric properties of four measures of noise sensitivity: A comparison", Journal of Environmental Psychology, 19 (3), (1999).

Stephen Grime is employed in the pollution control section at Telford Borough Council