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| 2. |
- Bengtsson, Johanna, 1974, et al.
(författare)
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Evaluations of effects due to low-frequency noise in a low demanding work situation
- 2004
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Ingår i: Journal of Sound and Vibration. - : Elsevier BV. - 0022-460X .- 1095-8568. ; 278:1-2, s. 83-99
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Tidskriftsartikel (refereegranskat)abstract
- Noise sources with a dominating content of low frequencies (20-200 Hz) are found in many occupational environments. This study aimed to evaluate effects of moderate levels of low-frequency noise on attention, tiredness and motivation in a low demanding work situation. Two ventilation noises at the same A-weighted sound pressure level of 45 dB were used: one of a low-frequency character and one of a flat frequency character (reference noise). Thirty-eight female subjects worked with six performance tasks for 4 h in the noises in a between-subject design. Most of the tasks were monotonous and routine in character. Subjective reports were collected using questionnaires and cortisol levels were measured in saliva. The major finding in this study was that low-frequency noise negatively influenced performance on two tasks sensitive to reduced attention and on a proof-reading task. Performances of tasks aimed at evaluating motivation were not significantly affected. The difference in work performance was not reflected by the subjective reports. No effect of noise was found on subjective stress or cortisol levels.
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| 3. |
- Bengtsson, Johanna, 1974, et al.
(författare)
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Sound characteristics in low frequency noise and their relevance for the perception of pleasantness
- 2004
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Ingår i: Acta Acoustica. ; 90:1, s. 171-180
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Tidskriftsartikel (refereegranskat)abstract
- Noise sources with a dominant content of low frequencies (20-200 Hz) are found in many occupational environments. Work efficiency has been found in two earlier studies to be impaired to a larger degree when working in a low frequency ventilation noise than when working in a flat frequency ventilation noise at the same A-weighted sound pressure level. Other previous studies indicate that different sound characteristics found in low frequency noise are important for the way in which low frequency noise affects humans, and better knowledge of these characteristics could lead to better methods for assessing low frequency noise in occupational environments. The aim of this study was to evaluate the influence of frequency balance between low and high frequencies, which affects the slope of the frequency spectra, and the modulation frequency on subjects´ perception of a pleasant low frequency noise. The results showed that the subjects preferred either a higher or a lower modulation frequency as compared to that of the original low frequency noise, both choices leading to less perceivable modulations. Furthermore, the subjects preferred a lower relative content of frequencies below 500 Hz, but only as long as the original low frequency noise contained modulations and the variations were made within a constant A-weighted sound pressure level. The results are discussed in relation to improved guidelines and to the previously suggested theory of slope of the frequency spectra and problems involved with the implementation of that theory.
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| 4. |
- Bengtsson Ryberg, Johanna, 1974, et al.
(författare)
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Low frequency noise in a paper mill control room
- 2004
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Ingår i: The 11th International Meeting on Low Frequency Noise and Vibration and its Control, 2004 30 August-1 September, Maastricht, The Netherlands. ; , s. 15-25
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Konferensbidrag (refereegranskat)
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| 7. |
- Pedersen, Eja, et al.
(författare)
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Perception and annoyance due to wind turbine noise : a dose–response relationship
- 2004
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 116:6, s. 3460-3470
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Tidskriftsartikel (refereegranskat)abstract
- Installed global wind power increased by 26% during 2003, with U.S and Europe accounting for 90% of the cumulative capacity. Little is known about wind turbines' impact on people living in their vicinity. The aims of this study were to evaluate the prevalence of annoyance due to wind turbine noise and to study dose–response relationships. Interrelationships between noise annoyance and sound characteristics, as well as the influence of subjective variables such as attitude and noise sensitivity, were also assessed. A cross-sectional study was performed in Sweden in 2000. Responses were obtained through questionnaires (n = 351; response rate 68.4%), and doses were calculated as A-weighted sound pressure levels for each respondent. A statistically significant dose–response relationship was found, showing higher proportion of people reporting perception and annoyance than expected from the present dose–response relationships for transportation noise. The unexpected high proportion of annoyance could be due to visual interference, influencing noise annoyance, as well as the presence of intrusive sound characteristics. The respondents' attitude to the visual impact of wind turbines on the landscape scenery was found to influence noise annoyance.
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| 8. |
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| 9. |
- Pedersen Sejer, C., et al.
(författare)
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An investigation of low frequency noise complaints
- 2004
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Ingår i: 11th Meeting on Low Frequency Noise and Vibration and its Control, 2004 30 Aug-1 Sep, Maastricht, The Netherlands. ; , s. 261-68
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Konferensbidrag (refereegranskat)
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| 11. |
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| 12. |
- Persson Waye, Kerstin, 1959, et al.
(författare)
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Cortisol response and subjective sleep disturbance after low-frequency noise exposure
- 2004
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Ingår i: Journal of Sound and Vibration. ; 277:3, s. 453-457
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Tidskriftsartikel (refereegranskat)abstract
- A previous experimental study showed that the cortisol response upon awakening was reduced following nights with low-frequency noise exposure. This study comprised a larger number of subjects and an extended period of acclimatisation nights. In total, 26 male subjects slept during five consecutive nights in a sleep laboratory. Half of the subjects were exposed to low-frequency noise (40 dBA) on the 4th night and had their reference night (24 dBA) on the 5th night, while the reverse conditions were present for the other half of the group. Subjective sleep disturbances were recorded by questionnaires and cortisol response upon awakening was measured in saliva. The results showed that subjects were more tired and felt less socially orientated in the morning after nights with low-frequency noise. Mood was negatively affected in the evening after nights with low-frequency noise. No effect of noise condition was found on the cortisol secretion. There was a significant effect of group and weekday, indicating that further methodological developments are necessary before saliva cortisol secretion can be reliably used as an indicator of noise-disturbed sleep.
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| 13. |
- Persson Waye, Kerstin, 1959
(författare)
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Effects of low frequency noise on sleep
- 2004
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Ingår i: Noise Health. - 1463-1741. ; 6:23, s. 87-91
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Tidskriftsartikel (refereegranskat)abstract
- Low frequency noise (20-200 Hz) is emitted by numerous sources in the society. As low frequencies propagate with little attenuation through walls and windows, many people may be exposed to low frequency noise in their dwellings. Sleep disturbance, especially with regard to time to fall asleep and tiredness in the morning, are commonly reported in case studies on low frequency noise. However, the number of studies where sleep disturbance is investigated in relation to the low frequencies in the noise is limited. Based on findings from available epidemiological and experimental studies, the review gives indications that sleep disturbance due to low frequency noise warrants further concern.
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