Noise is a prominent feature of the environment including noise from transport, industry and neighbours. Exposure to transport noise disturbs sleep in the laboratory, but not generally in field studies where adaptation occurs. Noise interferes in complex task performance, modifies social behaviour and causes annoyance. Studies of occupational and environmental noise exposure suggest an association with hypertension, whereas community studies show only weak relationships between noise and cardiovascular disease. Aircraft and road traffic noise exposure are associated with psychological symptoms but not with clinically defined psychiatric disorder. In both industrial studies and community studies, noise exposure is related to raised catecholamine secretion. In children, chronic aircraft noise exposure impairs reading comprehension and long-term memory and may be associated with raised blood pressure. Further research is needed examining coping strategies and the possible health consequences of adaptation to noise.

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Noise pollution: non-auditory effects on health

Exposure to noise constitutes a health risk. There is sufficient scientific evidence that noise exposure can induce hearing impairment, hypertension and ischemic heart disease, annoyance, sleep disturbance, and decreased school performance. For other effects such as changes in the immune system and birth defects, the evidence is limited. Most public health impacts of noise were already identified in the 1960s and noise abatement is less of a scientific but primarily a policy problem. A subject for further research is the elucidation of the mechanisms underlying noise-induced cardiovascular disorders and the relationship of noise with annoyance and nonacoustical factors modifying health outcomes. A high priority study subject is the effects of noise on children, including cognitive effects and their reversibility. Noise exposure is on the increase, especially in the general living environment, both in industrialized nations and in developing world regions. This implies that in the twenty-first century noise exposure will still be a major public health problem.

Noise exposure and public health.

Noise, a prototypical environmental stressor, has clear health effects in causing hearing loss but other health effects are less evident. Noise exposure may lead to minor emotional symptoms but the evidence of elevated levels of aircraft noise leading to psychiatric hospital admissions and psychiatric disorder in the community is contradictory. Despite this there are well documented associations between noise exposure and changes in performance, sleep disturbance and emotional reactions such as annoyance. Moreover, annoyance is associated with both environmental noise level and psychological and physical symptoms, psychiatric disorder and use of health services. It seems likely that existing psychiatric disorder contributes to high levels of annoyance. However, there is also the possibility that tendency to annoyance may be a risk factor for psychiatric morbidity. Although noise level explains a significant proportion of the variance in annoyance, the other major factor, confirmed in many studies, is subjective sensitivity to noise. Noise sensitivity is also related to psychiatric disorder. The evidence for noise sensitivity being a risk factor for psychiatric disorder would be greater if it were a stable personality characteristic, and preceded psychiatric morbidity. The stability of noise sensitivity and whether it is merely secondary to psychiatric disorder or is a risk factor for psychiatric disorder as well as annoyance is examined in two studies in this monograph: a six-year follow-up of a group of highly noise sensitive and low noise sensitive women; and a longitudinal study of depressed patients and matched control subjects examining changes in noise sensitivity with recovery from depression. A further dimension of noise effects concerns the impact of noise on the autonomic nervous system. Most physiological responses to noise habituate rapidly but in some people physiological responses persist. It is not clear whether this sub-sample is also subjectively sensitive to noise and whether failure to habituate to environmental noise may also represent a biological indicator of vulnerability to psychiatric disorder. In these studies noise sensitivity was found to be moderately stable and associated with current psychiatric disorder and a disposition to negative affectivity. Noise sensitivity levels did fall with recovery from depression but still remained high, suggesting an underlying high level of noise sensitivity. Noise sensitivity was related to higher tonic skin conductance and heart rate and greater defence/startle responses during noise exposure in the laboratory. Noise sensitive people attend more to noises, discriminate more between noises, find noises more threatening and out of their control, and react to, and adapt to noises more slowly than less noise sensitive people.(ABSTRACT TRUNCATED AT 400 WORDS)

Noise, Noise Sensitivity and Psychiatric Disorder: Epidemiological and Psychophysiological Studies

Background:Exposure to noise is highly prevalent in the workplace, and an etiologic association with cardiovascular disease has been hypothesized. Although there is evidence of hypertension among noise-exposed workers, evidence of heart disease has been less conclusive.Methods:We identified a cohort

https://www.jstor.org/stable/pdfplus/20485996.pdf

Occupational Exposure to Noise and Mortality From Acute Myocardial Infarction

This quasiexperimental field study explored the effect of noise attenuation on urinary cortisol excretion (sampled three times, at 6:30 and 10:30 AM and 1:30 PM) and reported fatigue and postwork irritability among 35 healthy industrial workers chronically exposed to high ambient noise levels (> 85 dB [A]) without using ear protectors. The results indicated that under conditions of chronic noise exposure the cortisol level at the end of the workshift was high and almost reached the morning level. This elevation in cortisol excretion was accompanied by high levels of accumulated fatigue and postwork irritability. Attenuating the noise reaching the eardrum by 30 to 33 dB, by fitting the same workers with earmuffs for a period of 7 working days, resulted in a significant improvement in both psychological and physiological stress reactions. Besides decreasing noise intensity, no other changes were made, either to ongoing work activities or to the other characteristics of the ambient noise. The cortisol level declined steadily during the workshift and exhibited the normal cortisol diurnal rhythm. At the end of the workshift, this level was significantly lower (P < .05) than that observed under the chronic noise-exposure condition. There was also a concomitant reduction in reported fatigue (P < .05) and postwork irritability (P < .01). These findings demonstrate the "net" contribution of ambient noise to elevating stress reactions to regular work demands.

The effects of chronic industrial noise exposure on urinary cortisol, fatigue and irritability: a controlled field experiment.

Non-auditory effects of noise were studied among 539 male workers from seven industries. The LAeq, assessed by personal noise dosimetry, has been used to study acute effects. Various indices of total noise exposure, involving level and duration, were developed for long-term effect studies. In the analysis close attention was paid to prevent confounding, e.g. by other adverse working conditions. As expected, hearing loss increased with total noise exposure. Tinnitus was related particularly to hearing loss. Dizziness and hoarseness, however, were not related with noise exposure in this study. Also no correlation could be demonstrated between blood pressure and total noise exposure after correction for age, relative weight and various confounding variables. Use of hearing protection, selection processes and incomplete analysis of interactions between independent variables are suggested for possible explanation. About two-thirds of the workers reported noise annoyance. Various aspects were mentioned, such as irritation, surprise and impairment of communication and perception. Mentally stressful tasks appeared to be the most noise-sensitive. Particularly annoying noise sources, mental work load and time pressure had a relatively large impact on noise annoyance in comparison with the influence of noise level (LAeq) itself. Stress responses were not simply related to the noise exposure level, although consistent positive relations could be demonstrated between symptoms of stress and noise annoyance. Various findings led to the conclusion that noise exposure together with stressful mental activities may lead to disturbed concentration, irritation and annoyance. Experienced stress in turn may render workers more susceptible to noise. To overcome some limitations of this study, cohort studies and studies designed to assess interaction-effects are recommended.

A. M. Souman

Papers

Non-auditory effects of noise in industry. VI. A final field study in industry.