Survey of noise exposure and background noise in call centers using headphones

Call centers represent one of the fastest growing industries. However, there are health and safety hazards unique to this new industry. One of these potential hazards is hearing impairment caused by headsets. In this study, noise exposure assessment was performed at 21 call centers and for 117 operators. Although call center background noise does not contribute to noise exposure, it impacts working conditions and influences the headset volume setting. It was therefore measured at the same time as exposure to noise. Results revealed that although the risk of hearing impairment was generally low, exposure could exceed the European Union regulation upper and lower exposure action values. Besides exposure to noise, background noise levels are often high with regard to recommendations for office workers. Results are discussed and some recommendations are given, issued from on-site observations. Their application is intended to ensure the absence of excessive exposure to noise and improve acoustic comfort.     

Assessment of telephone operators' exposure to sound through headphones

We estimated the level of noise that telephone operators were exposed to through headphones by a two-step method using an artificial ear technique and a manikin technique. In the artificial ear technique, the sound pressure level (Leq) of the total work hours was 81.5 dB, whereas the Leq of the total duration of phone calls was 89.3 dB. Therefore, we conducted a more accurate measurement by the manikin technique (ISO11904-2). By this method, we could simulate the headphone-wearing condition of the workers and convert the measurements to a diffuse-field related L(Aeq). By this manikin technique, the corrected L(Aeq) of the total work hours was 68.3 dB, whereas the corrected L(Aeq) of the total duration of call was 76.6 dB, which was below the standard of the Occupational Exposure Limits of the Japan Society of Occupational Health. We confirmed that in a workplace where the background noise is low (51.3 dBA), a good signal-noise ratio is maintained so that operators don't have to listen to loud sounds through headphones. Neither the gender nor the type of the telephone equipment of the callers affected the sound pressure levels.     

The use of hearing protection devices by older adults during recreational noise exposure

A population-based study to assess the use of hearing protection devices by older adults during noisy recreational activities was performed. The population-based Epidemiology of Hearing Loss Study was designed to measure the prevalence of hearing loss in adults residing in Beaver Dam, Wisconsin. The use of hearing protection devices during noisy recreational activities was assessed by performing three examinations over a period of 10 years (1993-1995, no. of participants (n)=3753, aged 48-92 years; 1998-2000, n=2800, aged 53-97 years; 2003-2005, n=2395, aged 58-100 years). The recreational activities included hunting, target shooting, woodworking/carpentry, metalworking, driving loud recreational vehicles, and performing yard work using either power tools or a chain saw. The prevalence of using hearing protection devices during any of these activities increased with time (9.5%, 15.0%, and 19.9% at baseline, 5 years, and 10 years, respectively). However, the use of hearing protection devices remained low for most activities. Those under the age of 65 were twice as likely to use hearing protection devices during noisy activities than were older adults. Men, those with a hearing handicap, and those with significant tinnitus were more likely to use hearing protection devices. Smokers and the less educated were less likely to use hearing protection devices. The results demonstrated that many adults expose themselves to potentially damaging recreational noise, leaving them at risk for hearing loss.     

Effects of changed aircraft noise exposure on the use of outdoor recreational areas

This paper examines behavioural responses to changes in aircraft noise exposure in local outdoor recreational areas near airports. Results from a panel study conducted in conjunction with the relocation of Norway's main airport in 1998 are presented. One recreational area was studied at each airport site. The samples (n = 1,264/1,370) were telephone interviewed about their use of the area before and after the change. Results indicate that changed aircraft noise exposure may influence individual choices to use local outdoor recreational areas, suggesting that careful considerations are needed in the planning of air routes over local outdoor recreational areas. However, considerable stability in use, and also fluctuations in use unrelated to the changes in noise conditions were found. Future studies of noise impacts should examine a broader set of coping mechanisms, like intra- and temporal displacement. Also, the role of place attachment, and the substitutability of local areas should be studied.     

Occupational noise exposure and hearing protector use in Canadian lumber mills

Noise exposure is probably the most ubiquitous of all occupational hazards, and there is evidence for causal links between noise and both auditory and nonauditory health effects. Noise control at source is rarely considered, resulting in reliance on hearing protection devices to reduce exposure. A comprehensive noise survey of four lumber mills using a randomized sampling strategy was undertaken, resulting in 350 full-shift personal dosimetry measurements. Sound frequency spectrum data and information on hearing protector usage was collected. A determinants-of-exposure regression model for noise was developed. Mean (L(eq,8hr)) exposure level was 91.7 dBA, well above the exposure British Columbia (BC) limit of 85 dBA. Of 52 jobs for which more than a single observation was made, only 4 were below the exposure limit. Twenty-eight jobs had means over 90 dBA, and four jobs had means over 100 dBA. The sawmill and by-products departments of the lumber mills had the highest exposure to low frequency noise, while the planing and saw filing areas had the highest exposure to high frequency noise. Hearing protector use was greatest among those exposed above 95 dBA, and among those exposed between 85 and 95 dBA, self-reported use was 84% for 73% of the time. The determinants of exposure model had an R(2) of 0.52, and the within-participant correlation was 0.07. Key predictors in the final model were mill; enclosure and enclosure construction material; and certain departments, jobs, and noise sources. The study showed that workers in lumber mills are highly exposed to noise, and although the prevalence of the use of hearing protection is high, their use is unlikely to provide complete protection again noise-induced hearing loss at the observed exposures. Determinants of noise exposure modeling offers a good method for the quantitative estimation of noise exposure.     

Occupational noise exposure in the printing industry

The noise exposures of 274 printing production workers in 34 establishments in the New York city area were monitored. Results showed that 43% were exposed to 8-hr time-weighted average (TWA) noise exposures of 85 dBA or greater and that 14% were exposed to 8-hr TWAs of 90 dBA or greater. Within the press department, web press workers were exposed to significantly greater mean 8-hr TWAs than sheetfed press workers. In general, a greater percentage of the workers in the bindery departments were exposed to potentially harmful noise than workers in the press departments. Results of this study indicate that many workers in the printing industry may be at risk of occupational hearing loss. Further research is needed to determine the extent of hearing impairment in this group of workers.     

Validity of self-reported occupational noise exposure

In all epidemiological studies the validity of self-reported questionnaire data is an important issue as the exposure assessment based on such data is a major source of bias in the risk estimation. A validation study was conducted based on a case–control study including 94 acoustic neuroma cases and 191 matched controls from the German Interphone Study to investigate the level of agreement between self-reported occupational noise exposure and a job-exposure-matrix (JEM) on noise exposure derived from a lifetime occupation calendar. The JEM was generated based on measurement data collected in the literature for various occupations. Level of agreement was investigated by using sensitivity, specificity, kappa coefficient and the Youden-Index. The receiver operating characteristics curve yielded an optimal cut point of 80 decibel(Acoustic) (dB(A)) to dichotomize noise exposure, displaying a moderate agreement between self-reported exposure and the JEM-based exposure (kappa of 0.53) that was slightly higher for cases than controls (kappas of 0.62 and 0.48). The agreement was only slightly lower if the longest held job or the last held job were used instead of the loudest job of the lifetime job history. The cut point of 80 dB(A) corresponds with regulations for workers safety with a recommendation to wear noise protection. The good levels of agreement between self-reported high occupational noise exposure compared with JEM-data, together with no substantial differences between cases and controls, suggest that self-reported data on occupational noise exposure is a valid exposure metric. Noise exposure appears to be appropriate if only exposure information on the last or the longest held job is available.

Gender perspectives in psychometrics related to leisure time noise exposure and use of hearing protection

The purpose of the present study was to investigate possible gender differences regarding psychometric scales measuring risk perception in noisy situations, attitudes towards loud music, perceived susceptibility to noise, and individual norms and ideals related to activities where loud music is played. In addition the purpose was to analyze whether these variables are associated with protective behavior such as the use of hearing protection. A questionnaire was administered to a Swedish sample including 543 adolescents aged 16 to 20. The result revealed significant gender differences for all the psychometric scales. In addition, all psychometric measures were associated with hearing protection use in musical settings. Contrary to previous studies, gender did not contribute to any explanation of protective behavior by itself in the analysis. One conclusion is that although gender does not contribute by itself for the explanation of protective behavior, gender may affect psychological variables such as risk perception, attitudes and perceived susceptibility and that these variables may in turn be valuable for decision-making and protective behavior in noisy situations. Although women tend to be more 'careful' psychologically, they nevertheless tend to behave in the same way as men as regards actual noise-related risk taking.     

Cognitive after-effects of vibration and noise exposure and the role of subjective noise sensitivity

This study investigated the effects on attention performance after exposure to noise and whole-body vibration in relation to subjective noise sensitivity. Sixteen high and 16 low sensitivity male students, as determined by the Weinstein Noise Sensitivity Questionnaire, participated in a within-subjects experiment. Noise and vibration stimuli similar to those usually occurring in forestry vehicles were presented either individually, combined or not at all in four separate sessions lasting approximately 44 min. After exposure, participants completed an attention task and made subjective ratings of alertness. No main effect of noise sensitivity was observed in MANOVA, thus the data was pooled with the data from a pilot study using the exact same procedure without using a noise sensitivity inclusion criterion. The combined data revealed performance degradation in the attention task after exposure to vibration, regardless as to whether it was presented alone or in combination with noise. Increased ratings of alertness after vibration exposure and decreased ratings of alertness after noise exposure were also found. Neither synergistic nor antagonistic effects were observed from the combined noise and vibration exposure.     

Assessment of the noise exposure of call centre operators

Call centres now play a major role in the daily operations of financial, technology and utility companies, as well as public bodies. It is predicted that 2002 will see 2.3% of the total British workforce employed in call centres. However, local authority enforcement officers, unions, voluntary organizations, employers and employees have all expressed concern that there are hazards to health and safety unique to this new and developing industry. One of the potential hazards reported in the press is hearing damage from using headsets. In a Health & Safety Executive funded project, the noise exposure of 150 call centre operators was evaluated, in call centres which included financial services, home shopping and telecommunications services. The results show that the daily personal noise exposure of these call centre operators is unlikely to exceed the 85 dB(A) action level defined in the Noise at Work Regulations 1989. The risk of hearing damage is therefore extremely low. Exposure to higher noise levels is possible, for example from fax tones, holding tones and high pitched tones from mobile phones. However, the duration of these events is likely to be short and they are therefore unlikely to have a significant effect on the operators' overall noise exposure. A practical method of limiting exposure to unexpected high noises from headsets is to ensure that the headsets incorporate acoustic shock protection that meets the requirements of the Department of Trade and Industry specification 85/013. In the UK, this limiter ensures any noise above 118 dB is not transmitted through the headset. Operators should receive regular training on the headset and telephone equipment they are using. This training should include correct use of the headset and the volume control facilities, and advice on how and when to clean and maintain the headsets.