Exposure to high noise levels among fire fighters is well documented and increases the risk for noise-induced hearing loss. NIOSH recommends measures to promote better hearing health through the use of quieter equipment, better work practices, hearing protection devices, and implementation of effective hearing loss
Source : http://www.cdc.gov/niosh/docs/wp-solutions/2013-142/pdfs/2013-142.pdf
A fresh article by researchers including Dan Hasson at Karolinska Institute and the Stress Research Institute in Stockholm, Sweden concludes that emotional exhaustion in women affects their sound perception in a negative way. The sample of subjects were taken from SLOSH (Swedish Longitudinal Occupational Survey of Health) and followed up with additional data collection. After being provoked with an acute stress task women who had scored high on emotional exhaustion also showed a greater sensitivity to sounds. This study supports the theory that hearing problems such as hyperacusis (auditory sensitivity) may be stress induced and that emotional exhaustion should be taken into account in the diagnosis and treatment of hearing problems.
Source : Hasson D, Theorell T, Bergquist J, Canlon B . Acute Stress Induces Hyperacusis in Women with High Levels of Emotional Exhaustion. PLoS ONE 8(1) 2013. http://dx.doi.org/10.1371/journal.pone.0052945
Should we just accept that it takes 20 metres for the sound level of someone's voice to drop to a comfortable non-distracting level, or should we reduce this to 10 metres so that workgroup-to-workgroup distractions are minimized?
Source : http://www.acousticbulletin.com/EN/2013/04/how_far_do_you_speak_in_the_of.html
In this publication we include all, or almost all, the valid formulas of sound levels in different types of rooms. We will explain all the theoretical basis of each of them, starting with reflected intensity, both classical and revised theories, the total sound level and its uses in concert venues. We will also deal with empirical formulas mainly for classrooms, churches and religious buildings and industrial use. However, the main significance of this work is not only the wide range of formulas exposed but also that we have found the explanation of why the reverberation radius, or distance radius, cannot exist in the revised theory. This finding can help that the revised theory of M. Barron be slightly modified to apply it to any room for several uses, other than concerts
Source : Higini Arau-Puchades. Sound Pressure Levels in Rooms: A Study of Steady State Intensity, Total Sound Level, Reverberation Distance, a New Discussion of Steady State Intensity and Other Experimental Formulae. Noise notes, Vol.11, No 4 / December 2012, http://dx.doi.org/10.1260/1475-47126.96.36.199
Background: Long-term exposure to hand-held vibrating tools may cause the hand arm vibration syndrome (HAVS) including vibration induced white fingers and sensorineural symptoms. The aim was to study early neurosensory effects by quantitative vibrotactile and monofilament tests in young workers with hand-held vibration exposure. Methods: This cross-sectional study consisted of 142 young, male machine shop and construction workers with hand-held exposure to vibrating tools. They were compared with 41 non-vibration exposed subjects of the same age-group. All participants passed a structured interview, answered several questionnaires and had a physical examination including the determination of vibrotactile perception thresholds (VPTs) at two frequencies (31.5 and 125 Hz) and Semmes Weinstein's Monofilament test. Results: In the vibration exposed grlogistic multiple regression analysis (result of monofilament oup 8% of the workers reported episodes of tingling sensations and 10% numbness in their fingers. Approximately 5--10% of the exposed population displayed abnormal results on monofilament tests. The vibrotactile testing showed significantly increased VPTs for 125 Hz in dig II bilaterally (right hand, p = 0.01; left hand, p = 0.024) in the vibration exposed group.A multiple regression analysis (VPT - dependent variable; age, height, examiner and five different vibration dose calculations -- predictor variables) in dig II bilaterally showed rather low R2-values. None of the explanatory variables including five separately calculated vibration doses were included in the models, neither for the total vibration exposed group, nor for the highest exposed quartile.A logistic multiple regression analysis (result of monofilament testing - dependent variable; age, height, examiner and five vibration dose calculations -- predictor variables) of the results of monofilament testing in dig II bilaterally gave a similar outcome. None of the independent variables including five calculated vibration doses were included in the models neither for the total exposed group nor for the highest exposed quartile. Conclusion: In spite of the fairly short vibration exposure, a tendency to raised VPTs as well as pathologic monofilament test results was observed. Thus, early neurophysiologic symptoms and signs of vibration exposure may appear after short-term exposure also in young workers.
Source : Lars Gerhardsson, Lage Burstrom, Mats Hagberg, Ronnie Lundstrom, Tohr Nilsson. Quantitative neurosensory findings, symptoms and signs in young vibration exposed workers. Journal of Occupational Medicine and Toxicology 2013, 8:8 doi:10.1186/1745-6673-8-8
Keywords: Vibrotactile thresholds; Monofilament test
Current methods for evaluating seat vibration to predict vibration discomfort assume the same frequency weightings and axis multiplying factors can be used at the seat surface and the backrest irrespective of the backrest inclination. This experimental study investigated the discomfort arising from whole-body vertical vibration when sitting on a rigid seat with no backrest and with a backrest inclined at 0° (upright), 30°, 60°, and 90° (recumbent). Within each of these five postures, 12 subjects judged the discomfort caused by vertical sinusoidal whole-body vibration (at frequencies from 1 to 20 Hz at magnitudes from 0.2 to 2.0 m s−2 r.m.s.) relative to the discomfort produced by a reference vibration (8 Hz at 0.4 m s−2 r.m.s.). With 8-Hz vertical vibration, the subjects also judged vibration discomfort with each backrest condition relative to the vibration discomfort with no backrest. The locations in the body where discomfort was experienced were determined for each frequency at two vibration magnitudes. Equivalent comfort contours were determined for the five conditions of the backrest and show how discomfort depends on the frequency of vibration, the presence of the backrest, and the backrest inclination. At frequencies greater than about 8 Hz, the backrest increased vibration discomfort, especially when inclined to 30°, 60°, or 90°, and there was greater discomfort at the head or neck. At frequencies around 5 and 6.3 Hz there was less vibration discomfort when sitting with an inclined backrest.
Source :Bazil Basri, Michael J. Griffin. Predicting discomfort from whole-body vertical vibration when sitting with an inclined backrest. Applied Ergonomics, Vol. 44, no 3, May 2013, p.423–434. http://dx.doi.org/10.1016/j.apergo.2012.10.006 Backrest angle; Whole-body vibration; Ride comfort; Prediction model
Sound Advice contains practical guidelines on the control of noise at work in music and entertainment. Representatives of music and entertainment industries together with Environmental Health Officers and the Health and Safety Executive (HSE) prepared the guidance. For more details see About Sound Advice. On this site you will find out what you can do to avoid the harmful effects of prolonged exposure to noise - for yourself and for the people you employ or work with. It is closely related to a printed guide.
Exposure to loud noise continues to be the largest cause of hearing loss in the adult population. The problem of NIHL impacts a number of disciplines. US standards for permissible noise exposure were originally published in 1968 and remain largely unchanged today. Indeed, permissible noise exposure for US personnel is significantly greater than that allowed in numerous other countries, including for example, Canada, China, Brazil, Mexico, and the European Union. However, there have been a number of discoveries and advances that have increased our understanding of the mechanisms of NIHL. These advances have the potential to impact how NIHL can be prevented and how our noise standards can be made more appropriate.
Source : Editors:Colleen G. Le Prell, Donald Henderson, Richard R. Fay, Arthur N. Popper. Noise-Induced Hearing Loss : Scientific Advances, Springer , 2012. http://link.springer.com/book/10.1007/978-1-4419-9523-0/page/1
(Quelques pages peuvent être consultées à l'intérieur de chaque chapitre)
Noise control devices such as panels and barriers, when of high efficiency, generally are of difficult acquisition due to high costs turning in many cases their use impracticable, mainly for limited budget small-sized companies. There is a huge requirement for new acoustic materials that have satisfactory performance, not only under acoustic aspect but also other relevant ones and are of low cost. Vegetable fibers are an alternative solution when used as panels since they promise satisfactory acoustic absorption, according to previous researches, exist in abundance, and derive from renewable sources. This paper, therefore, reports on the development of panels made from vegetable fibers (coconut, palm, sisal, and açaí), assesses their applicability by various experimental (flammability, odor, fungal growth, and ageing) tests, and characterize them acoustically in terms of their sound absorption coefficients on a scale model reverberant chamber. Acoustic results point out that the aforementioned fiber panels play pretty well the role of a noise control device since they have compatible, and in some cases, higher performance when compared to commercially available conventional materials.
Source : Leopoldo Pacheco Bastos, Gustavo da Silva Vieira de Melo, and Newton Sure Soeiro. Panels Manufactured from Vegetable Fibers: An Alternative Approach for Controlling Noises in Indoor Environments. Advances in Acoustics and VibrationVolume 2012 (2012), Article ID 698737, 9 p. http://dx.doi.org/10.1155/2012/698737
This paper presents several ways in which the propagation of acoustic waves produced by an industrial noise source can be attenuated by identifying the optimal location of an acoustic screen near the noise source. Six types of acoustic screens were used, made of six types of materials (of the category used in the field of construction), with or without sound absorbing qualities. The noise source was placed in four different positions in front of the acoustic screen. The microphone was placed in 16 recording positions, at four distances and four heights. The experimentally obtained values indicate that the efficiency of the acoustic screen is optimal when the screen is placed at a reduced distance from the noise source, in a centered position. To obtain a high degree of sound pressure level attenuation, one can choose among variants with at least two screening walls positioned in a "V" form.
Source : Tomozei, C.; Nedeff, V.; Lazar, G.; Ciobanu, E. Reducing of the sound pressure level in industrial areas by screening noise sources. Noise & Vibration Worldwide, vol. 43, no 10, p. 28-38. http://dx.doi.org/10.1260/0957-45188.8.131.52
This paper investigates the effect of noise and the effect of a redundant impulsive auditory alarm signal on production operators' response to machine downtime in a semiconductor manufacturing system. Machine uptime is essential for productive and efficient production system and therefore downtime calls for an immediate response. Given a higher machine-to-man ratio, there is a difficulty in achieving quick response to machine downtime. For this end, ergonomic tower lamps with visual and auditory displays are used in most semiconductor manufacturing system to alert production operators and therefore minimize response time. The results of this study showed that a less noisy environment enhances operators' response to machine downtime. This proves literatures' claim on the limited capacity of human perception to achieve sharper focus on tasks when noise is present. Furthermore, the results also proved that a redundant auditory alarm signal aside from visual alarm at moderately high to high noise exposure; 85-90 dBA and >90 dBA, respectively, does not improve responses as discussed by literatures. It could be, as literatures say, that on persistent exposure to alarm signals beyond permissible noise level of 85 dBA, production operators may experience alarm fatigue phenomenon - a state of failing to hear the signals. Thus, redundant auditory alarm signals are only added costs and can further increase ambient noise which may, in effect, possibly induce health-related problems.
Source : Lanndon A. Ocampo, Eppie E. Clark, Alaine Liggayu. Effect of noise and redundant auditory alarm signal on semiconductor production operators' response to machine downtime. Noise & Vibration Worldwide, vol. 43, no 11, p. 21-28. http://dx.doi.org/10.1260/0957-45184.108.40.206
noise, fatigue, visual-auditory signal, alarm, semiconductor
Noise-induced hearing loss (NIHL) still remains a problem in developed countries, despite reduced occupational noise exposure, strict standards for hearing protection and extensive public health awareness campaigns. Therefore NIHL continues to be the focus of noise research activities. This paper summarizes progress achieved recently in our knowledge of NIHL. It includes papers published between the years 2008-2011 (in English), which were identified by a literature search of accessible medical and other relevant databases. A substantial part of this research has been concerned with the risk of NIHL in the entertainment sector, particularly in professional, orchestral musicians. There are also constant concerns regarding noise exposure and hearing risk in "hard to control" occupations, such as farming and construction work. Although occupational noise has decreased since the early 1980s, the number of young people subject to social noise exposure has tripled. If the exposure limits from the Noise at Work Regulations are applied, discotheque music, rock concerts, as well as music from personal music players are associated with the risk of hearing loss in teenagers and young adults. Several recent research studies have increased the understanding of the pathomechanisms of acoustic trauma, the genetics of NIHL, as well as possible dietary and pharmacologic otoprotection in acoustic trauma. The results of these studies are very promising and offer grounds to expect that targeted therapies might help prevent the loss of sensory hair cells and protect the hearing of noise-exposed individuals. These studies emphasize the need to launch an improved noise exposure policy for hearing protection along with developing more efficient norms of NIHL risk assessment.
Sliwinska-Kowalska M, Davis A. Noise-induced hearing loss. Noise Health [serial online] 2012 [cited 2013 Mar 18];14:274-80. Available from: http://www.noiseandhealth.org/text.asp?2012/14/61/274/104893
Noise is omnipresent and impacts us all in many aspects of daily living. Noise can interfere with communication not only in industrial workplaces, but also in other work settings (e.g. open-plan offices, construction, and mining) and within buildings (e.g. residences, arenas, and schools). The interference of noise with communication can have significant social consequences, especially for persons with hearing loss, and may compromise safety (e.g. failure to perceive auditory warning signals), influence worker productivity and learning in children, affect health (e.g. vocal pathology, noise-induced hearing loss), compromise speech privacy, and impact social participation by the elderly. For workers, attempts have been made to: 1) Better define the auditory performance needed to function effectively and to directly measure these abilities when assessing Auditory Fitness for Duty, 2) design hearing protection devices that can improve speech understanding while offering adequate protection against loud noises, and 3) improve speech privacy in open-plan offices. As the elderly are particularly vulnerable to the effects of noise, an understanding of the interplay between auditory, cognitive, and social factors and its effect on speech communication and social participation is also critical. Classroom acoustics and speech intelligibility in children have also gained renewed interest because of the importance of effective speech comprehension in noise on learning. Finally, substantial work has been made in developing models aimed at better predicting speech intelligibility. Despite progress in various fields, the design of alarm signals continues to lag behind advancements in knowledge. This summary of the last three years' research highlights some of the most recent issues for the workplace, for older adults, and for children, as well as the effectiveness of warning sounds and models for predicting speech intelligibility. Suggestions for future work are also discussed.
Source : Brammer AJ, Laroche C. Noise and communication: A three-year update. Noise Health [serial online] 2012 [cited 2013 Mar 18];14:281-6. Available from: http://www.noiseandhealth.org/text.asp?2012/14/61/281/104894
International Commission on Biological Effects of Noise (ICBEN) Team 8 deals with the effects of combined "agents" in the urban and work place settings. Results presented at the ICBEN conference indicate that some pesticides, more specifically the organophosphates, and a wider range of industrial chemicals are harmful to the auditory system at concentrations often found in occupational settings. Effects of occupational noise on hearing are exacerbated by toluene and possibly by carbon monoxide. Several of the chemicals studied found to be potentially toxic not only to hair cells in the cochlea but also to the auditory nerve. In urban environments, team 8 focuses on additive and synergetic effects of ambient stressors. It was argued that noise policies need to pay attention to grey areas with intermediate noise levels. Noteworthy is also stronger reactions to vibrations experienced in the evening and during the night. An innovative event-based model for sound perception was presented.
Source : Leroux T, Klaeboe R. Combined Exposures: An update from the International comission on biological effects of noise. Noise Health 2012;14:313-4. http://www.noiseandhealth.org/article.asp?issn=1463-1741;year=2012;volume=14;issue=61;spage=313;epage=314;aulast=Leroux
The association between noise and cardiovascular disease has been studied for several decades and the weight of evidence clearly supports a causal link. Nevertheless, many questions remain, such as the magnitude and threshold level for adverse effects of noise, how noise and other cardio-toxic pollutants (such as particulate matter) may interact in disease causation, identification of vulnerable populations, of exposure modifiers (i.e., location of bedrooms) and of other effect-modifiers (i.e., gender), and how epidemiologic methodology can be improved. This review describes contributions to literature over the past 3 years in the area of noise and CVD in general, with particular focus on these questions.
Davies H, Kamp IV. Noise and cardiovascular disease: A review of the literature 2008-2011. Noise Health [serial online] 2012 [cited 2013 Mar 18];14:287-91. Available from: http://www.noiseandhealth.org/text.asp?2012/14/61/287/104895
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