Occupational Noise Levels Research Articles

Application of Bayesian Decision Analysis to Estimate Occupational Noise Levels from Limited Exposure Data

In recent years, Bayesian statistical modeling approaches have emerged as valuable tools in Industrial Hygiene (IH), particularly in situations with limited exposure data. This paper delves into the application of Bayesian Statistical Models, specifically Bayesian Decision Analysis (BDA), to analyze occupational noise exposure data within two Similar Exposure Groups (SEGs) of groundskeeping workers, addressing the pervasive issue of high noise levels exceeding 85 dBA. The primary aim is to estimate exposure levels based on the location of the exposure profiles for the SEGs within the AIHA® Exposure Control Categories (ECCs) 0-4, later modified and expanded to AIHA-ECC 0-5. This study employs BDA to estimate noise exposures among groundskeepers, emphasizing the scarcity of literature on BDA in noise exposure rating. Groundskeepers, facing potential risk of hearing impairment due to prolonged exposure, constitute a crucial and critical demographic, with nearly one million individuals in the United States alone. Noise data from the two SEGs was analyzed by using the Exposure Assessment Strategies Committee—EASC- AIHA® IHData Analyst for BDA modeling, complemented with the AIHA IHSTAT™ for certainty rating. The resulting posterior graphs were utilized to categorize exposure profiles into respective AIHA ECCs relative to noise OEL. These findings provide valuable insights, indicating a posterior probability of approximately 43.5% and 56.5% with 95% confidence that noise exposure levels fall within AIHA ECC 3 and AIHA ECC 4, respectively. However, while the 95% percentile decision statistics suggest exposure values lower than the OEL, the Upper Tolerance Limit (UTL) significantly surpass the OEL indicating low certainty regarding these exposure values for employees. Notably, the UTLs suggest that the SEGs are experiencing noise levels above the legally required 90 dBA for more than 5% of the time, which is an unacceptable scenario. Recommendations include implementing protective strategies such as regular training, surveillance, and monitoring, alongside engineering control strategies and mandatory use of personal protective equipment. These results underscore the critical need for refining judgments about noise exposures based on variability within and between employees, suggesting the use of additional statistical tools such as ANOVA (single-multivariate), MATLAB, and Python.

Evaluation and implication of noise and vibration levels to the operators and proxy population around selected block molding industries in Ibadan, Nigeria

Introduction: Block-making industries owned by private individuals are cited in cities to utilize the existing market opportunity of supplying concrete blocks to developers. The study aimed to measure noise and vibration levels at selected block-molding industries and assess their health implications. Methods: The study design involves twenty-five block molding industries randomly selected in the Ibadan metropolis. These industries voluntarily agreed to participate in the research, and measurements were done between January and May 2022. The noise and vibration levels were measured using a digital multi-function environmental meter, Model DT-8820, and a vibration meter, Model VM-6360, respectively. Results: An overall mean noise level of 101.81 dB(A), 85.62 dB(A), 76.40 dB(A), 70.21 dB(A), 65.91 dB(A), and 63.61 dB(A) at 0, 10, 20, 30, 40 m, respectively, away from the source to residential buildings were obtained. Results indicate that the noise level at 0 m and 10 m exceeded the occupational noise level standard. The results obtained for the vibration levels on the hand of the operators ranged from 42.2 ms-2 to 59.7 ms-2 and these exceeded the occupational vibration level standard. This may indicate that the operators of the block-moulding machine may be exposed to various adverse health detriments due to high noise and vibration levels at their workplace. Conclusion: The study recommends using safety gadgets such as hearing protection and anti-vibration gloves for workers in these industries. Moreover, environmental education and awareness should be carried out, and residential structures should be situated at least 20 meters from the block industries.

The Status of Occupational Noise in Some Selected Factories on Libya

In this paper occupational noise levels atselected factories were measured and compared with the international permissible levels using the integratingsound level meter (Quest 2800) during the year 2007.The calibration of the instrument was carried out beforeand after each measurement using the acousticcalibrator (Quest CA-12B calibrator). The methodwhich was followed was measuring the sound pressurelevel of the different noise sources over a broadfrequency band covering the audible frequency rangeusing the (Octave band filter, model OB-100),disregarding variation with time.From the obtained results, some noise levels whichwere recorded were within the permissible levels i.e.below 90 dBA and some noise levels were higher thanthe permissible limit as at Janzoor textile factory(95dBA), Benghazi Macaroni factory (100dBA), andnear the air blowers at Zletin cement factory, Benghazicement factory (97-100 dBA) in these cases suggestionswere made to minimize the problem.

Impact of occupational noise exposure on the hearing level in hospital staffs: a longitudinal study.

The study aimed to evaluate the impact of occupational noise on hearing loss among healthcare workers using audiometry. A longitudinal study was conducted with a six-month follow-up period in a hospital with 21 participants, divided into high-noise-exposure (HNE) and low-noise-exposure (LNE) groups. Mean noise levels were higher in the HNE group (70.4 ± 4.5 dBA), and hearing loss was measured using pure-tone audiometry at baseline and follow-up. The HNE group had significantly higher mean threshold levels at frequencies of 0.25kHz, 0.5kHz, 4.0kHz, and an average of 0.5, 1, 2, and 4kHz (all p-values < 0.05) after the follow-up period. After adjusting for confounding factors, the HNE group had significantly higher hearing loss levels at 0.25kHz, 0.5kHz, and average frequencies of 0.5, 1, 2, and 4kHz compared to the LNE group at the second measurement. Occupational noise levels above 65 dBA over six months were found to cause significant threshold changes at frequencies of 0.25kHz, 0.5kHz, and an average of 0.5-4.0kHz. This study highlights the risk of noise-induced hearing loss among healthcare workers and emphasizes the importance of implementing effective hearing conservation programs in the workplace. Regular monitoring and assessment of noise levels and hearing ability, along with proper use of personal protective equipment, are crucial steps in mitigating the impact of occupational noise exposure on the hearing health of healthcare workers.

Association between occupational noise and obesity: a retrospective cohort study in China.

To determine the relationship between occupational noise, and obesity and body mass index (BMI) changes. Baseline data were collected from participants (n = 1264) who were followed for 6years in a retrospective study. The noise exposure level (LAeq,8h) was determined by equivalent continuous weighted sound pressure levels using the fixed-point surveillance method for noise monitoring. The cumulative noise exposure (CNE) level was determined using the equal energy formula, which is based on exposure history and level. The incidence of obesity at low (RR = 2.364, 95% CI 1.123-4.739]), medium (RR = 3.921, 95% CI 1.946-7.347]), high (RR = 5.242, 95% CI 2.642-9.208]), and severe noise levels (RR = 9.322, 95% CI 5.341-14.428]) was higher risk than the LAeq,8h control level. The risk of obesity among participants exposed to low (RR = 2.957, 95% CI 1.441-6.068]) and high cumulative noise levels (RR = 7.226, 95% CI 3.623-14.415]) was greater than the CNE control level. For every 1dB(A) increase in LAeq,8h, the BMI increased by 0.063kg/m2 (95% CI 0.055-0.071], SE = 0.004). For every 1dB(A) increase in the CNE, the BMI increased by 0.102kg/m2 (95% CI 0.090-0.113], SE = 0.006). Occupational noise is related to the incidence of obesity. The occupational noise level and occupational noise cumulative level were shown to be positively correlated with an increase in BMI.

Evaluation of Central Auditory Processing in Individuals with Occupational Noise exposure

Abstract Background Prolonged exposure to high levels of occupational noise can cause damage to hair cells in the cochlea and result in permanent noise-induced cochlear hearing loss. Consequences of cochlear hearing loss on speech perception and psychophysical central auditory abilities have been well documented. Objectives the aim of this research was to explore central auditory processing in individuals with history of occupational noise exposure. Subjects and method sixty subjects aged between 20 and 50 years divided into 2 groups; control group (thirty normal healthy subjects), study group (thirty subject with history of occupational noise exposure). They were subjected to Basic audiological evaluation :Pure tone audiometry for frequencies 250-8000 Hz for air conduction and 500-4000 Hz for bone conduction, Speech reception threshold (SRT) using Arabic spondee words list (Soliman et al., 1985) and speech discrimination scores using Arabic phonetically balanced words (Soliman, 1976). And Tympanometry, central auditory processing questionnaire and Psychophysical central auditory tests that will be discussed later. Results Statistically significant difference was found between the study group and control group regarding left Dichotic digits test versionII (p = 0.020), The mean of SPIN either at Right or Left ear for study group was depressed in comparison to normal individuals, those differences were statistically highly significant (p &amp;lt; 0.001). Furthermore, there was a Highly statically significant difference in TCST (30%,60%), GIN test and DPT between study and control groups (p &amp;lt; 0.001) either at Right or Left ear. Conclusions Patients with occupational noise exposure had poor performance in all central auditory tests when compared with control. This means that occupational noise exposure can lead to impaired central auditory processing with subsequent in adults

Occupational noise level exposures outside and inside agricultural tractor cabs

The farm tractor fleet in the Brazilian market has increased. They are machines known to emit much noise. Noise can cause severe damage and disturbance in people who work directly with and around these machines. Therefore, the work aimed to evaluate the noise levels emitted by two cab farm tractors of different engine power, analyzing the effect of engine speed and distance radius from the noise source on occupational health. The noise level outside and inside of the tractor cab, the attenuation index, and the noise level reduction provided by the cab sound insulation were determined. Attenuation indexes and noise reduction ratings were satisfactory in studying the noise levels inside and outside the tractor cab. The tractor with the most power in the engine has better sound insulation compared to those lowest power. The noise levels that operators are exposed to in the cab were lower than the limits established by Brazilian government laws. On the other hand, outside the cab, the noise levels emitted by the tractor of greater power are not safe for the workers' health if they are at a distance radius from the noise source of less than 7 m, requiring the use of an ear protector.

ORTHOPAEDIC INSTRUMENTS AND ORTHOPAEDIC OPERATIONS CAN EXCEED NOISE REGULATION: A SYSTEMATIC REVIEW

Industries such as agriculture, construction and military have stringent rules about hearing protection due to the risk of noise induced hearing loss (NIHL). Due to the use of power tools, orthopaedic staff may be at risk of the same condition. The UK Health and Safety Executive (HSE) have clear standards as to what is deemed acceptable occupational noise levels on an A-weighted and C weighted scale. This review is aimed to assess evidence on noise exposure testing within Orthopaedic theatres to see if it exceeds the HSE regulations.A targeted search of online databases PUBMED and EMBASE was conducted using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) principles. This review was registered prospectively in PROSPERO. An eligibility criterion identifying clinical studies which assessed noise exposure for Orthopaedic staff in theatres were included. Noise exposure data was extracted from these studies and a comparison was made with A weighted and C weighted acceptable exposure levels as quoted in the HSE regulations.Fourteen papers were deemed eligible, which reviewed 133 Orthopaedic operations and 64 Orthopaedic instruments. In total, 61% (81 of 132) of Orthopaedic operations and 70% (45 of 64) of instruments exceeded the noise regulations on an A weighted scale. 22% (10 of 46) of operations exceeded the maximum C weighted peak acceptable noise level.Orthopaedic instruments and operations can exceed safe occupational noise levels. NHS Trusts have clear policies about noise exposure in the workplace but have yet to identify Orthopaedic theatres as a potential at risk area. Orthopaedic staff need education, monitoring and protection whereas Employers and Occupational Health should consider assessments to identify at risk staff in Orthopaedic theatres and offer preventative methods from NIHL.

Occupational exposure to noise and dust in Swedish soft paper mills and mortality from ischemic heart disease and ischemic stroke: a cohort study

ObjectiveTo elucidate whether occupational noise exposure increases the mortality from ischemic heart disease (IHD) and stroke, and if exposure to paper dust modified the risks.MethodsWe studied 6686 workers from soft paper mills, with occupational noise exposure, < 85 dBA, 85–90 dBA and > 90 dBA, and high (> 5 mg/m3) exposure to paper dust. Person-years 1960–2019 were stratified according to gender, age, and calendar-year. Expected numbers of deaths were calculated using the Swedish population as the reference and standardized mortality ratios (SMR) with 95% confidence intervals (95% CI) were assessed.ResultsSMR for IHD was 1.12 (95% CI 0.88–1.41) for noise < 85 dBA, 1.18 (95% CI 0.90–1.55) for 85–90 dBA, and 1.27 (95% CI 1.10–1.47) among workers exposed > 90 dBA. Joint exposure to high noise exposure and high exposure to paper dust resulted in slightly higher IHD mortality (SMR 1.39, 95% CI 1.15–1.67). SMR for ischemic stroke was 0.90 (95% CI 0.37–2.15) for noise < 85 dBA, 1.08 (95% CI 0.45–2.59) for 85–90 dBA, and 1.48 (95% CI 0.99–2.00) among workers exposed > 90 dBA. High noise exposure and high exposure to paper dust resulted in higher ischemic stroke mortality (SMR 1.83, 95% CI 1.12–2.98).ConclusionNoise levels > 90 dBA was associated with increased IHD mortality. Combined exposures of noise and paper dust may further increase the risks. Our results do not provide support for a causal relationship for ischemic stroke. Residual confounding from smoking has to be considered. Workers need to be protected from occupational noise levels exceeding 90 dBA.

Fan-noise reduction of data centre telecommunications’ server racks, with an acoustic metamaterial broadband, low-frequency sound-absorbing liner

An acoustic metamaterial is evaluated successfully as a means to reduce axial fan noise in an IT server rack application. The continuing growth in demand for cloud-based memory storage is outpacing sustainable energy management which still requires the axial fan as a fundamental component in temperature control technologies. As chip temperatures increase, additional numbers of more powerful fans are required to run faster with the result that data centres have become unsafe working environments due to the acoustic output exceeding prescribed occupational noise level limits. Noise isolation using soundproof cabinets is expensive and impractical in data centres which seek to reduce floor space and communication losses. Instead, in this work, a 15 mm deep acoustic liner solution is proposed being the approach taken in the aeronautics sector to reduce aeroengine noise which, similarly, is a flow duct problem. The acoustic metamaterial adopted here is the recently developed Segmented Membrane Sound Absorber (SeMSA) which can be tailored for low frequency, broadband and tonal noise in a thin form-factor and which can be used in a grazing flow configuration. An equivalent circuit model developed for the SeMSA allows its design to be optimised to attenuate a typical server fan’s frequency spectrum. An array of manufactured rectangular SeMSA cells was embedded in a “deflector plate”, which is an existing component in a server rack. The deflector plate was implemented in a custom-built fan sound power rig, tested in an hemi-anechoic chamber and compared to a hardwall case and to PU foam. A relative overall decrease of 2.5 dBA was achieved for the SeMSA deflector plate liner which corresponds to a 43.9% decrease in overall sound emissions, which using a material thickness of only 15 mm, signifies an almost twofold increase in the time required for hearing damage to occur. A 3 dBA drop was achieved at the blade passing frequency of 620 Hz, while relative drops of 1–2.5 dBA were achieved from 2000–8000 Hz.

Tinnitus Prevalence and Associated Factors among Dental Clinicians in the United Arab Emirates.

Dental clinicians are at increased risk for developing tinnitus due to exposure to high levels of occupational noise. This study aimed to determine tinnitus prevalence and associated factors among dental clinicians. Interviews were conducted with 150 randomly selected dental clinicians using a questionnaire. Noise levels were measured at three points of time at the operating area. Tinnitus was reported in 19.33% of the participants. The average noise level was significantly higher among participants with tinnitus compared to those without the condition. More participants complained of intermittent tinnitus and the rest had the constant type, with the latter being significantly more bothersome. The weekly average time of using high-speed handpieces, suction and electric handpieces, age and experience had a significant effect on the presence of tinnitus. Only 2.7% of the participants reported the use of a hearing protection device. Tinnitus is a common finding among dental clinicians especially those with higher levels of occupational noise and more frequent use of noise-generating equipment. Knowledge of tinnitus prevalence aids in realizing the extent of its impact and making informed decisions. These results call for improved awareness of the negative impact of clinically-generated noise and emphasize the importance of preventive measures and periodic audiometry exams.

Prevention of noise-induced hearing loss by rational appointment algorithm in periodontal, restorative and prosthetic treatments: A method study

Dentists are at risk of noise-induced hearing loss (NIHL). Dental treatment equipment has high-intensity noise levels. Occupational noise levels of multi-unit dental clinic are higher than private clinic and are at further increased risk of NIHL. This study aims to develop a noise-reducing appointment system in multi-unit dental clinics using treatment duration and steps noisemap. Restorative, periodontal, and prosthetic dental procedure noise levels were measured in a multi-unit dental clinic. A procedure noise map was created by measuring the amount of noise in the treatment time interval and the silent treatment period. The appointment algorithm was created according to this noise map. Control and 7 test simulation appointment algorithms were tested. The control group was simulated in six units simultaneously with conventional hour-based appointment algorithm. Test groups were simulated according to the appointment algorithm based on the treatment steps noisemap. Six-unit dental clinic was simulated under the dBmap system. While 2 of the 6 units in the test groups are in noise producing treatment steps, the other 4 seats are planned to operate without noise. According to treatment steps noisemap, test groups operated two-unit simultaneously at different timings. The distribution of noise producing units in the clinic was simulated in 7 groups (T1-T7). The mean noise measurements in all tested groups were significantly lower than in the control group. Periodontal treatment mean occupational noise level (68 dB) was higher than restorative (61 dB) and prosthetic treatment (59 dB). Control room mean occupational noise measurement was 68,54 dB, and test groups mean occupational noise measurements were between 57,19 –63,98 dB. The difference between control and tested groups was significantly different(p=0,0009). Occupational noise was significantly reduced with the noise reduction-based appointment method. Further studies are needed with different treatment procedures and validation studies in clinical settings.

Mechanized Wood Extraction: Impacts on Operators’ Hearing Health

The activity of the mechanized extraction of wood, carried out by means of self-propelled forest machines, consists of moving the wood cut inside the forest stand from the planted forests to the roadside. During displacements, these machines normally travel over forest residues and stumps, which can demand greater motor power from the engine, in addition to the possible increase in occupational noise levels. In this context, we evaluated whether, when operating different self-propelled forest machines in the wood extraction of planted Eucalyptus forests, operators are exposed to different levels of occupational noise, especially to thresholds above those established for prevention purposes. Occupational noise data were collected during the workday, weighing six self-propelled forest machine operators who performed the wood-extraction operation, performed by two forwarders, two self-loading tractors, and two grapple skidders, in three areas with Eucalyptus plantations located in the southeastern region of Brazil. The sound-pressure level was collected using two integrative meters following the strategic measurement criterion recommendation for the whole day in the guidelines of the acoustic determination of occupational noise exposure and analyzed according to the American Conference of Government Industrial Hygienists. Operators of forest machines for the mechanized extraction of wood were exposed to occupational noise levels above the recommended level, which can affect health and well-being; this occupation also required above-average levels of attention during the execution of work activities.

SARS-CoV-2 seroprevalence and risk factors among meat packing, produce processing, and farm workers.

Meat packing, produce processing, and farm workers are known to have an elevated risk of COVID-19, but occupational risk factors in this population are unclear. We performed an observational cohort study of meat packing, produce processing, and farm workers in North Carolina in fall 2020. Blood, saliva, and nasal turbinate samples were collected to assess for SARS-CoV-2 seropositivity. Risk factors for SARS-CoV-2 seropositivity were investigated using chi-square tests, two-sample t-tests, and adjusted risk ratio analyses. Among 118 enrolled workers, the baseline SARS-CoV-2 seroprevalence was 50.0%. Meat packing plant workers had the highest SARS-CoV-2 seroprevalence (64.6%), followed by farm workers (45.0%) and produce processing workers (10.0%), despite similar sociodemographic characteristics. Compared to SARS-CoV-2 seronegative workers, seropositive workers were more likely to work in loud environments that necessitated yelling to communicate (RR: 1.83, 95% CI: 1.25-2.69), work in cold environments (RR: 1.58, 95% CI: 1.12-2.24), or continue working despite developing symptoms at work (RR: 1.63, 95% CI: 1.14-2.32). After adjusting for age and working despite symptoms, high occupational noise levels were associated with a 1.72 times higher risk of SARS-CoV-2 seropositivity (95% CI: 1.16-2.55). Half of food processing workers showed evidence of past SARS-CoV-2 infection, a prevalence five times higher than most of the United States population at the time of the study. Work environments with loud ambient noise may pose elevated risks for SARS-CoV-2 transmission. Our findings also highlight the disproportionate burden of COVID-19 among underserved and economically disadvantaged Latinx communities in the United States.

An evaluation of machine operator exposure to occupational noise during harvesting and extraction operations in Brazilian eucalyptus plantations

ABSTRACT Wood harvesting operations involve mechanized and semi-mechanized machines that expose operators to occupational noise. It was verified that the emission of occupational noise levels in the harvest of mechanized and semi-mechanized wood in Brazilian forests planted with eucalyptus were in compliance with Directive 2003/10/EC. Noise data were collected using two personal-use integrative meters. The lower action level of 80 dB(A), the upper action level of 85 dB(A) and the exposure limit of 87 dB(A) were evaluated. The results showed that 16.6% of the operators were exposed to thresholds above the lower action level, but remained below the upper level of 85 dB(A), 8.3% of the operators were exposed to occupational noise levels above the upper action level, without exceeding the exposure limit of 87 dB(A) and 25% of operators were exposed to levels above the exposure limit. Therefore, the occupational noise levels achieved when harvesting mechanized and semi-mechanized wood in forests planted with eucalyptus do not comply with Directive 2003/10/EC.

Exposure to Occupational Noise

Physical agent noise can be considered one of the main disturbances that compromise the occupational health of self-propelled forest machine operators. We evaluated whether occupational noise levels emitted by self-propelled forest machines employed in the full tree system are in accordance with both the National Institute for Occupational Safety and Health and ISO 1999:2013 standards, while also proposing mitigating measures aimed at protecting the operators hearing. Seventeen operators, who performed wood harvesting operations in Eucalyptus forests in Brazil, were analyzed. Noise levels were collected in a daily shift of eight hours as recommended by the Acoustics – Determination of occupational noise exposure - Engineering method for full-day measurements (ISO 9612:2009). The standards adopted for the evaluation were the exposure action value of 80 dBA and the exposure limit of 85 dBA based on the National Institute for Occupational Safety and Health – NIOSH and on Acoustics – Estimation of noise-induced hearing loss (ISO 1999:2013) Directive 2003/10/EC. The operators were arranged in homogeneous groups according to the Acoustics recommendation – Determination of occupational noise exposure - Engineering method for full-day measurements (ISO 9612:2009), classified by the operations of felling, skidding of tree bundles and bucking. The results showed that 17 self-propelled forest machines exceeded the exposure action value of 80 dBA, of which 10 machines exceeded the exposure limit of 85 dBA. It was concluded that the levels of occupational noise emitted by self-propelled forest machines used in the full tree system are higher than those recommended by both standards, National Institute for Occupational Safety and Health and ISO 1999:2013. Therefore, the allocation of self-propelled forest machines to homogeneous groups allows inferring mitigation actions that protect operators' hearing. The correct use of hearing protectors during the daily workday provides hearing protection for operators in mechanized wood harvesting. Adoption of actions such as maintenance of cabin seals and mechanical components, breaks for fatigue relief, reduction of daily working hours and rotation of operators in different self-propelled forest machines can mitigate the damage to the occupational health of operators.

Fraction of acute work-related injuries attributable to hazardous occupational noise across the USA in 2019

IntroductionThe contribution of hazardous noise—a ubiquitous exposure in workplaces—to occupational injury risk is often overlooked. In this ecological study, the fraction of US workplace acute injuries resulting in days away...

Evaluation of Occupational Noise Exposure in a Plastic Manufacturing Industry: A Case Study

Industrial workers need a safe working environment to ensure their wellbeing is protected while performing tasks. Occupational noise is one of the most prevalent problems in industries due to nature of the industry. Therefore, this paper aimed to evaluate the occupational noise exposure in one of the plastic factories in Klang Valley, Malaysia. Noise measurement has been done in all production lines, crushing department, packaging department and officers’ area. The noise measurements were taken 1 to 3 metres from the source of noise at several points for each line and departments using sound level meter. Average noise level at all measurement location noted LAeq less than 80 dBA, except one point in line B and the crushing area. The packaging department recorded the lowest noise level, with LAeq 64.8 dBA and LAmax of 69.2 dBA. While, the crushing department is the noisiest area in the factory, with LAmax 105 dBA and LAeq 100.9 dBA. The average noise level at majority location in the factory is less than 80 dBA which means it is at a safe range. The workers do not need any personal hearing protection equipment during working, which was according to the Occupational Safety &amp; Health (Noise Exposure) Regulations 2019 noise regulations in Malaysia, except the crushing area only. In conclusion, evaluation of noise exposure in each section can provide a good understanding of the occupational noise level experienced by different workers at different departments. It can help the management to strategize and plan the noise control approach, especially at the area that may have risk of hearing loss for their workers.

The “cost” of noise at work: an occupational injustice among low wage workers and communities

BACKGROUND AND AIM: Noise exposure is ubiquitous in the US and has been associated with various health outcomes. Chronic occupational noise exposure of an 8-hour time weighted average (TWA) ≥85 A-weighted decibels (dBA) leads to permanent noise-induced hearing loss, which has major social impacts and may cost $100 billion annually in lost wages alone. It is estimated that tens of millions of workers are exposed to hazardous levels of occupational noise. Understanding potential occupational and environmental injustices in the distribution of occupational noise across communities and worker income groups is important to examine whether those exposed to hazardous levels of occupational noise are also disproportionately burdened populations. METHODS: Publicly available noise measurements from the US noise job exposure matrix (JEM) and wage estimates from the Bureau of Labor Statistics (BLS) Occupational Employment Statistics (OES) were utilized in mixed-effects logistic regression to analyze (1) national-level job-title noise exposure and the odds of earning $39,810 (median national salary), and (2) metropolitan/nonmetropolitan- (M/NM) level population-weighted occupational noise estimates and the odds of a M/NM area earning $36,020 (median M/NM-level salary). RESULTS:A one-dBA increase in the average noise exposure experienced at work is significantly associated with 1.19 (95% CI: 1.03, 1.38) times higher odds of earning $39,810, and 1.21 (95% CI: 1.03, 1.42) higher odds when controlling for total employment count. A one-dBA increase in a M/NM area’s population-weighted occupational noise estimate is significantly associated with 2.46 (95% CI: 1.50, 4.03) higher odds of a M/NM area earning $36,020, and 1.75 (95% CI: 1.06, 2.89) times higher odds when controlling for rural/urban area. CONCLUSIONS:Higher occupational noise exposure is unequally distributed among lower wage-earning jobs and communities. KEYWORDS: Noise, occupational exposures, socio-economic factors, environmental disparities

Effect of Unmeasured Time Hours on Occupational Noise Exposure Assessment in the Shipbuilding Process in Korea.

Occupational noise is known to be one of the most hazardous risk factors, frequently exceeding the exposure limit thus causing hearing loss and other health outcomes among many field workers in various industries and workplaces. This study aims to characterize the levels of occupational noise exposure during the daily working hours and break periods (sampling preparation and lunch break), identify work-related characteristics affecting the noise exposure levels when including or excluding the break periods and finally determine the most effective approach for occupational noise exposure assessment by using the Korean and U.S. OSHA’s guidelines. A total of 1575 workers employed by a large shipbuilding company participated in this study, and the historical exposure datasets of noise dosimeters, collected from 2016 to 2018, were classified by characteristics. A threshold level (TL) for the noise dosimeter was set as a value of 80 dBA during the break periods, including the preparation time for sampling instruments and one hour for the lunch break. The shipbuilding workers were exposed to high levels of occupational noise during the break periods, especially for those working in heating, grinding, and power processes in the painting-related departments. Out of 1575 samples, most cases were related to the preparation time (N = 1432, 90.9%) and lunch break (N = 1359, 86.9%). During the break time, the levels of noise exposure were measured depending on task-specific characteristics. When including the break time, the noise levels increased by approximately 1 dBA during the break, combining 0.8 dBA in the lunch hours and 0.2 dBA for the preparation of the sampling instrument. When excluding the break time, the levels of noise exposure collected using a Korean Occupational Safety and Health Administration (KOSHA) guide tended to be underestimated compared to those using the U.S. OSHA method. When including the break times, the proportion of noise exposure levels exceeding the compliance exposure limit declined from 37.9% to 34.5%, indicating that the break times might affect the decrease in the noise exposure levels. Taken together, shipbuilding workers could possibly be exposed to much greater amounts of noise exposure during break times in the shipbuilding processes, and the noise exposure levels in the department of painting were high. Therefore, it is recommended that industrial hygienists collect exposure monitoring data of occupational noise one hour after their job tasks begin and then consecutively monitor the noise exposure levels for at least 6 h including the break periods for each day.