Evy Öhrström

Aircraft and road traffic noise and children's cognition and health: a cross-national study

BACKGROUND Exposure to environmental stressors can impair childrens health and their cognitive development. The effects of air pollution, lead, and chemicals have been studied, but there has been less emphasis on the effects of noise. Our aim, therefore, was to assess the effect of exposure to aircraft and road traffic noise on cognitive performance and health in children. METHODS We did a cross-national, cross-sectional study in which we assessed 2844 of 3207 children aged 9-10 years who were attending 89 schools of 77 approached in the Netherlands, 27 in Spain, and 30 in the UK located in local authority areas around three major airports. We selected children by extent of exposure to external aircraft and road traffic noise at school as predicted from noise contour maps, modelling, and on-site measurements, and matched schools within countries for socioeconomic status. We measured cognitive and health outcomes with standardised tests and questionnaires administered in the classroom. We also used a questionnaire to obtain information from parents about socioeconomic status, their education, and ethnic origin. FINDINGS We identified linear exposure-effect associations between exposure to chronic aircraft noise and impairment of reading comprehension (p=0.0097) and recognition memory (p=0.0141), and a non-linear association with annoyance (p<0.0001) maintained after adjustment for mothers education, socioeconomic status, longstanding illness, and extent of classroom insulation against noise. Exposure to road traffic noise was linearly associated with increases in episodic memory (conceptual recall: p=0.0066; information recall: p=0.0489), but also with annoyance (p=0.0047). Neither aircraft noise nor traffic noise affected sustained attention, self-reported health, or overall mental health. INTERPRETATION Our findings indicate that a chronic environmental stressor-aircraft noise-could impair cognitive development in children, specifically reading comprehension. Schools exposed to high levels of aircraft noise are not healthy educational environments.

Longitudinal surveys on effects of changes in road traffic noise—annoyance, activity disturbances, and psycho-social well-being

The adverse effects of long-term exposure to a high volume of road traffic were studied in socio-acoustic surveys in 1997 and in 1999 after a substantial reduction in road traffic. The results obtained in 1997 showed a similar response pattern as in previously performed studies in the area in 1986 [Ohrstrom, J. Sound Vib. 122, 277–290 (1989)]. In 1999, road traffic had been reduced from 25 000 to 2400 vehicles per day, and this resulted not only in a large decrease in annoyance and activity disturbances, but also in a better general well-being. The results suggest that a reduction in both noise and other pollutants from road traffic contribute to these effects. To be able to use the outdoor environment and to have the possibility to keep windows open is essential for general well-being and daily behavior, which implies that access both to quiet indoor and outdoor sections of the residency is of importance for achievement of a healthy sound environment. More knowledge of long-term health consequences of exposure to noise and simultaneous pollutants from road traffic is needed. Studies should focus more on “softer” health outcomes and well-being than hitherto and preferably be performed in connection with traffic abatement measures.

Risk of hypertension from exposure to road traffic noise in a population-based sample

Objectives: To assess the association between hypertension and traffic noise. Methods: The prevalence and incidence of hypertension were examined in a Swedish municipality partly affected by noise from a highway (20 000 vehicles/24 h) and a railway (200 trains/24 h). A-weighed 24 h average sound levels (LAeq,24h) from road and railway traffic were calculated at each residential building using a geographical information system and a validated model. Physician-diagnosed hypertension, antihypertensive medication and background factors were evaluated in 1953 individuals using postal questionnaires (71% response rate). Prevalence ratios and odds ratios (ORs) were calculated for different noise categories. Based on year of moving into the residence and year of diagnosis, person-years and incidence rates of hypertension were estimated, as well as relative risks including covariates, using Poisson and Cox regression. Results: When road traffic noise, age, sex, heredity and body mass index were included in logistic regression models, and allowing for >10 years of latency, the OR for hypertension was 1.9 (95% CI 1.1 to 3.5) in the highest noise category (56−70 dBA) and 3.8 (95% CI 1.6 to 9.0) in men. The incidence rate ratio was increased in this group of men, and the relative risk of hypertension in a Poisson regression model was 2.9 (95% CI 1.4 to 6.2). There were no clear associations in women or for railway noise. Conclusions: The study shows a positive association between residential road traffic noise and hypertension among men, and an exposure–response relationship. While prevalence ratios were increased, findings were more pronounced when incidence was assessed.

Noise annoyance with regard to neurophysiological sensitivity, subjective noise sensitivity and personality variables

To evaluate the relation between annoyance to environmental noise, general neurophysiological sensitivity, subjective noise sensitivity and other individual characteristics, experiments were undertaken in which 93 subjects assessed their subjective annoyance after exposure to noise under laboratory conditions. Evaluations were made of the discomfort threshold for pulsating sound, the light discomfort, and heat and cold discomfort. The heart rate and discomfort after exposure to a series of impulse noises was also determined. Subjective noise sensitivity, attitudes to noise, mood and personality characteristics of the subjects were evaluated using questionnaires. The results show that the annoyance after exposure to noise was not closely related to the general neurophysiological sensitivity, measured as discomfort threshold for noise, heat, cold and light; or to the heart rate reaction or discomfort after exposure to impulse noise. The annoyance was highly correlated with subjectively reported noise sensitivity and with the attitude to noise. There was also a relationship with neuroticism, measured with the EPI scale. It is suggested that the subjective noise sensitivity, attitude and neuroticism for the definition of noise sensitivity be defined in future studies of long term effects of noise exposure.

Effects of noise on mental performance with regard to subjective noise sensitivity

SummaryObjective and subjective effects of moderate levels of recorded traffic noise [Leq = 55 dB(A) and 75 dB(A)] on mental performance were studied in a laboratory setting. A total of 45 subjects (23 males and 22 females) were investigated with respect to subjective noise sensitivity (SNS). Four cognitive tasks were applied involving different psychological functions: Short-Term Memory (STM), Search and Memory 5 (SAM 5) (vigilance), Hidden Figures (HF) (spatial reasoning) and Mental Arithmetic (MA) (parallel processing). Three groups of 15 subjects were defined according to their scores on Weinsteins Noise Sensitivity Scale as tolerant, moderately sensitive or highly sensitive to noise. A similar level of performance was observed in the three groups under quiet conditions [30 dB(A) Leq], but under noisy conditions significant differences (P<0.05) were seen between them on the STM (words) and MA (total results) tasks, and the lowest performance accuracy was demonstrated by the noise-sensitive subjects. SNS was the primary factor responsible for these differences. There were no significant differences between the groups in respect of the SAM 5 and HF tasks, under either quiet or noisy conditions. Annoyance while performing tasks under noisy conditions was regularly and significantly higher among subjects judged to be noise sensitive on Weinsteins scale, as compared with those judged to have low or moderate SNS.

SLEEP DISTURBANCE EFFECTS OF TRAFFIC NOISE--A LABORATORY STUDY ON AFTER EFFECTS

Abstract Body movements during sleep and subjective sleep quality, as well as mood and performance were investigated after exposure to intermittent and continuous traffic noise during the night. In a first experiment, six young subjects slept in the laboratory for five nights; in a second experiment 12 subjects slept six consecutive nights in the laboratory. A good dose-response relationship was obtained between intermittent noise and subjective sleep quality: i.e., the higher the noise level, the poorer the sleep quality. A similar dose-response relationship was found for body movements immediately following noise peaks during nights with intermittent noise. Performance and mood tended to be worse after intermittent noise. However, these effects did not increase with an increase in noise levels. Compared with intermittent noise, continuous noise had a significantly smaller effect on sleep quality. Mood and performance were not worse after continuous noise. The results suggest that increased attention should be paid to peak noise levels when standards for nocturnal noise are set.

Sleep disturbances from road traffic and ventilation noise-laboratory and field experiments

Abstract The aims of this study were to assess the effects on sleep of different types of noise exposures (road traffic, ventilation and combination of noise from road traffic and ventilation) and compare effects on sleep both in laboratory and in field settings. Eighteen subjects slept 1 week in the laboratory and 1 week in their home and their sleep was evaluated with wrist actigraphs and questionnaires on sleep and mood. In the laboratory, judged sleep quality was decreased by 22% during nights with exposure to road traffic noise in the laboratory compared to the quiet reference night. The combined noise from ventilation and road traffic caused more awakenings; worse sleep quality (−25%) and more movements reported by questionnaire. None of these significant results were detected by actigraphy. Noise from ventilation caused a decrease in judged sleep quality by 12%, while sleep assessed by actigraph indicated better sleep as compared with the quiet reference night. When comparing sleep with traffic noise exposure in the laboratory and in the home the results show no differences on sleep effects.

Sleep disturbance, psycho-social and medical symptoms—A pilot survey among persons exposed to high levels of road traffic noise

Abstract A pilot survey was undertaken to elucidate sleep quality, as well as psycho-social and medical symptoms and mood, among people who had lived for many years in an area with high levels of road traffic noise during night hours and inhabitants of a quiet control area: 106 personal interviews were performed and specific questionnaires on sleep and mood answered by 63 persons during three consecutive days. It was found that both sleep quality and mood (social orientation, activity, wellbeing and extroversion) were depressed in the noisy area as compared with a control area. Symptoms of tiredness, headache and nervous stomach disorders were more frequent. A significant relationship between sensitivity to noise and sleep quality was also found. From this pilot study hypotheses may be formulated about a relationship between environmental noise and different psycho-social and medical symptoms. It is suggested that similar studies on a larger scale are performed to elucidate long-term effects of noise.

Annoyance due to single and combined sound exposure from railway and road traffic.

Environmental noise is a growing and well recognized health problem. However, in many cases people are exposed not to a single noise source-for example, road, railway, or aircraft noise-but to a combination of noise exposures and there is only limited knowledge of the effects on health of exposure to combined noise sources. A socio-acoustic survey among 1953 persons aged 18-75 years was conducted in residential areas exposed to railway and road traffic noise with sound levels ranging from L(Aeq,24h) 45-72 dB in a municipality east of Gothenburg, Sweden. The objectives were to assess various adverse health effects, including annoyance, and to elucidate the impact of exposure to single and combined noise sources. In areas exposed to both railway and road traffic, the proportion annoyed by the total traffic sound environment (total annoyance) was significantly higher than in areas with one dominant noise source (rail or road traffic) with the same total sound exposure (L(Aeq,24h,tot)). This interaction effect was significant from 59 dB and increased gradually with higher sound levels. Effects of the total sound exposure should be considered in risk assessments and in noise mitigation activities.

Psycho-social effects of traffic noise exposure

Abstract In this paper a study of psycho-social effects of exposure to high levels of road traffic noise is presented. A questionnaire was constructed to evaluate not only annoyance reactions and sleep disturbance effects of noise, but also more long-term effects on psycho-social well-being (PSW). PSW was evaluated by 26 questions concerning depression, relaxation, activity, passivity, general well-being and social orientation. The postal questionnaire was answered by 151 persons in a quiet city area and 97 persons in an area exposed to an L eq level of 72 dB(A). The results showed that a higher proportion of those who lived in the noisy area in apartments with windows facing the street more often felt depressed. Those who had windows facing the courtyard, in the noisy area, however, were not more depressed that those who lived in the quiet area. Methodological difficulties in this type of study are also discussed in the paper.