Railway noise annoyance and the importance of number of trains, ground vibration, and building situational factors.

Internationally accepted exposure-response relationships show that railway noise causes less annoyance than road traffic and aircraft noise. Railway transport, both passenger and freight transport, is increasing, and new railway lines are planned for environmental reasons. The combination of more frequent railway traffic and faster and heavier trains will, most probably, lead to more disturbances from railway traffic in the near future. To effectively plan for mitigations against noise and vibration from railway traffic, new studies are needed to obtain a better basis of knowledge. The main objectives of the present study was to investigate how the relationship between noise levels from railway traffic and general annoyance is influenced by (i) number of trains, (ii) the presence of ground borne vibrations, and (iii) building situational factors, such as orientation of balcony/patio and bedroom window. Socio-acoustic field studies were executed in residential areas; (1) with relatively intense railway traffic; (2) with strong vibrations, and; (3) with the most intense railway traffic in the country. Data was obtained for 1695 respondents exposed to sound levels ranging from L(Aeq,24h) 45 to 65 dB. Both number of trains and presence of ground-borne vibrations, and not just the noise level per se, are of relevance for how annoying railway noise is perceived. The results imply that, for the proportion annoyed to be equal, a 5 - 7 dB lower noise level is needed in areas where the railway traffic causes strong ground-borne vibrations and in areas with a very large number of trains. General noise annoyance was twice as high among residents in dwellings with balcony / patio oriented towards the railway and about 1.5 times higher among residents with bedroom windows facing the railway.

Survey context and question wording affects self reported annoyance due to road traffic noise: a comparison between two cross-sectional studies.

BACKGROUND: Surveys are a common way to measure annoyance due to road traffic noise, but the method has some draw-backs. Survey context, question wording and answer alternatives could affect participation and answers and could have implications when comparing studies and/or performing pooled analyses. The aim of this study was to investigate the difference in annoyance reporting due to road traffic noise in two types of surveys of which one was introduced broadly and the other with the clearly stated aim of investigating noise and health. METHODS: Data was collected from two surveys carried out in the municipality of Malmö, southern Sweden in 2007 and 2008 (n = 2612 and n = 3810). The first survey stated an aim of investigating residential environmental exposure, especially noise and health. The second survey was a broad public health survey stating a broader aim. The two surveys had comparable questions regarding noise annoyance, although one used a 5-point scale and the other a 4-point scale. We used geographic information systems (GIS) to assess the average road and railway noise (LAeq,24h) at the participants' residential address. Logistic regression was used to calculate odds ratios for annoyance in relation to noise exposure. RESULTS: Annoyance at least once a week due to road traffic noise was significantly more prevalent in the survey investigating environment and health compared to the public health survey at levels > 45 dB(A), but not at lower exposure levels. However no differences in annoyance were found when comparing the extreme alternatives "never" and "every day". In the study investigating environment and health, "Noise sensitive" persons were more likely to readily respond to the survey and were more annoyed by road traffic noise compared to the other participants in that survey. CONCLUSIONS: The differences in annoyance reporting between the two surveys were mainly due to different scales, suggesting that extreme alternatives are to prefer before dichotomization when comparing results between the two. Although some findings suggested that noise-sensitive individuals were more likely to respond to the survey investigating noise and health, we could not find convincing evidence that contextual differences affected either answers or participation.

Attractive "quiet" courtyards: a potential modifier of urban residents' responses to road traffic noise?

The present paper explores the influence of the physical environmental qualities of "quiet". courtyards (degree of naturalness and utilization) on residents' noise responses. A questionnaire study was conducted in urban residential areas with road-traffic noise exposure between L(Aeq,24h) 58 to 68 dB at the most exposed façade. The dwellings had "quiet" indoor section/s and faced a "quiet" outdoor courtyard (L(Aeq,24h) < 48 dB façade reflex included). Data were collected from 385 residents and four groups were formed based on sound-level categories (58-62 and 63-68 dB) and classification of the "quiet" courtyards into groups with low and high physical environmental quality. At both sound-level categories, the results indicate that access to high-quality "quiet" courtyards is associated with less noise annoyance and noise-disturbed outdoor activities among the residents. Compared to low-quality "quiet" courtyards, high-quality courtyards can function as an attractive restorative environment providing residents with a positive soundscape, opportunities for rest, relaxation and play as well as social relations that potentially reduce the adverse effects of noise. However, access to quietness and a high-quality courtyard can only compensate partly for high sound levels at façades facing the streets, thus, 16% and 29% were still noise annoyed at 58-62 and 63-68 dB, respectively. Implications of the "quiet"-side concept are discussed.

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.

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 [Ohrström, J. Sound Vib. 122, 277-290 (1989)]. In 1999, road traffic had been reduced from 25000 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.

Sleep Studies Before and After - Results and Comparison of Different Methods.

The effects of long-term exposure to road traffic noise on sleep quality were assessed using questionnaires and actimetry. Results obtained before and after reduction in road traffic were compared. Sleep quality was improved after the reduction of noise levels. There was some correlation between actimetry parameters and subjective parameters.

Sleep disturbances caused by road traffic noise - Studies in laboratory and field.

Field studies and laboratory experiments on noise-induced sleep disturbance show conflicting results and do not provide sufficient knowledge for valid exposure-effect relationships. It is also well known that habituation exists for awakenings whereas other effects such as heart rate reactions and minor EEG-reactions do not habituate. In this paper comparisons are made between findings from a series of laboratory and field studies on effects of road traffic noise on sleep performed by this athor. Possible reasons for the discrepancies found in various studies in laboratory and field are commented on and methods and research needs are discussed. Comparison of results obtained in research on perceived sleep quality parameters at this Department that used the same methods in laboratory and field studies showed fairly good agreement for difficulties in falling asleep and perceived sleep quality whereas awakening reactions were much less frequently reported in the field studies.