Permissible Noise Exposure Research Articles

Risk Ratio of Noise-Induced Hearing Loss in Mineral Ore Processing Industry Workers

The mining industry employs machines and equipment that generate noise. Noise is an unwanted sound that can cause discomfort to listeners, leading to health issues. One of the health problems caused by noise is Noise-Induced Hearing Loss (NIHL), a hearing impairment resulting from continuous exposure to hazardous noise levels. The Permissible Noise Exposure (PNE) value in the mining industry is set at 85 dB(A). This study aims to assess the risk of noise exposure in relation to the occurrence of NIHL among mineral ore processing workers in the mining industry in Indonesia. The study employs the epidemiological frequency measurement method Relative Risk Ratio (RR). The study categorizes workers into two groups: native mining industry workers and contractor workers in the mining industry. The RR results for each group are 2.68 and 2.76 (RR>1), respectively. These results indicate that the noise-exposed group is at a 2.68-2.76 times higher risk of experiencing NIHL compared to the non-exposed group. Noise exposure in the mining industry poses a high risk of NIHL to workers, necessitating control measures. Control measures involve reducing noise exposure using Personal Protective Equipment (PPE) such as earplugs for workers in noisy areas. The use of earplugs can reduce noise by around 24-32 dB(A). Additionally, some industrial companies conduct awareness programs to encourage workers to use earplugs or other PPE, known as the hearing conservation program.

Hubungan Masa Kerja Dengan Kejadian Gangguan Pendengaran Pada Karyawan PT. Riau Graindo Pekanbaru Tahun 2019

Background: Hearing loss is one of the occupational diseases. A noisy work environment as one of the impacts of the industrial sector. This is the most common cause of hearing loss. The National Institute of Health in 2012 reports that about 15% of Americans aged 20-69 years experience hearing loss in connection with work activities, because noise can cause hearing loss, the government sets standards that regulate permissible noise exposure. Hearing loss due to noise occurs slowly, in a matter of months to years. This is often not realized by the sufferer, so that when the patient starts complaining of hearing loss, it is usually already in an irreversible stage. Such conditions will affect labor productivity which will ultimately cause a decrease in the health of the workforce. In certain cases, hearing loss due to noise begins for 6 to 10 years after exposure to loud noises. PT. Riau Graindo was established on January 17, 1997 located in Desa Sidomulyo Barat Kecamatan Tampan Kota Pekanbaru, a publishing company under of Riau Pos Group (RPG), based in Pekanbaru. Research Objectives: To determine corelations of work period with the incidence of hearing loss in employees of PT. Riau Graindo Pekanbaru in 2019. Research Methods: This study was an observational analytic study with a cross sectional approach. Research Results: Majority of PT. Pekanbaru Graindo Pekanbaru that is > 5 years as many as 21 people (70%). The majority of employees of PT. Riau Graindo Pekanbaru experiencing hearing loss as many as 18 people (60%). Chi square test results obtained Pvalue = 0.001, it can be concluded that there is a relationship between work period and the incidence of hearing loss in the employees of PT. Riau Graindo Pekanbaru in 2019. Conclusion: It can be concluded that there is a relationship between working period and the incidence of hearing loss in the employees of PT. Riau Graindo Pekanbaru in 2019 with Pvalue = 0.001 smaller than α (0.05).

Acoustic safety assessment of palm oil mill workers

Mechanization of work processes in agro-based industries through the employment of improved tools and/or equipment powered by either fuel or diesel engines reduce tedium and drudgery on the workers as well as improve the overall productivity and production. However, it also leads to health threat to the workers through environmental noise pollution. This study assessed the occupational noise exposure of workers in three different palm oil mills. The noise level was measured using a noise metering device (model 1352) and noise descriptors (L10, L50, L90, Lav, LAeq, Total Sound Pressure Level (Tspl), DOSE (%) and TWA). The occupational health effects of noise exposure were deduced using a semistructured questionnaire. The noise exposure was assessed during the palm nut digestion, and nut and pulp separation job operations as the noise emanates from the diesel-powered engine, palm nut digester and nut and pulp separator. The average noise levels obtained from the palm oil mills during palm nut digestion, 99.36 (SD = 4.16) dBA and pulp separation, 98.18 (SD = 3.07) dBA, exceeded the recommended 85 dBA for an 8-hour exposure period permissible noise exposure limit standard by the NIOSH. The independent t-tests for noise level between off-working and working periods disclosed p < 0.05 – significant noise exposure. The self-reported effect of the noise exposure level on the workers was interference with communication - 100%, tinnitus - 70%, ringing sensation - 76.75%, and noise stress - 73.30% of the workers. This research will inform the operators of the need for appropriate personal protective equipment usage and equip Government regulatory agencies to make appropriate regulations in order to protect oil mill workers.

Screening for Noise-Induced Hearing Loss among Palm Oil Mill Workers in Peninsular Malaysia: A Comparison across Noise Exposure Levels

Background: Palm oil mill workers in Malaysia are exposed to hazardous levels of noise in the workplace, and thus are at risk of developing noise-induced hearing loss (NIHL). In 2019, Malaysia introduced a new noise regulation, which reduced the level of permissible noise exposure. Objectives: This study aims to determine the prevalence of NIHL among palm oil mill workers based on screening data and assess the effects of different noise exposure levels on NIHL. Methods: A cross-sectional study was conducted by analyzing data from noise risk assessment reports of selected mills and screening audiometric data from workers. NIHL was defined as bilateral high-frequency hearing loss. Results: The overall NIHL prevalence was 50.8%. Noise exposure level and age were significant predictors of NIHL among the workers. The risk of developing NIHL was high even for workers who were not categorized in the high-risk group. Conclusions: In view of the findings, a precautionary approach is needed when evaluating the risk of NIHL in the study population. Vulnerable groups of workers must be protected from occupational noise hazards through the implementation of effective hearing conservation programs in the workplace.

Noise reduction in power looms using nitrile rubber polymer

Noise pollution is major concern in textile industries. The excessive noise creates harmful effects on workers, working textile industries. This research paper presents reduction of noise in textile power loom with use of nitrile rubber as damper to reduce noise. The nitrile rubber has hardness value of 50 shore A. The noise is measured employing M370 Electret- microphone. Frequency and time response curves were obtained using Fast Fourier analyzer. From the frequency response in turn found attributes like sound pressure level, sound levels. The parameter such as Permissible Noise Exposure and Noise Exposure Dosage (NED) were determined. The amount of noise reduction were determined using NED. The use of damper provides the noise reduction in textile power loom.

Temporal Alterations to Central Auditory Processing without Synaptopathy after Lifetime Exposure to Environmental Noise.

People are increasingly exposed to environmental noise through the cumulation of occupational and recreational activities, which is considered harmless to the auditory system, if the sound intensity remains <80dB. However, recent evidence of noise-induced peripheral synaptic damage and central reorganizations in the auditory cortex, despite normal audiometry results, has cast doubt on the innocuousness of lifetime exposure to environmental noise. We addressed this issue by exposing adult rats to realistic and nontraumatic environmental noise, within the daily permissible noise exposure limit for humans (80dB sound pressure level, 8h/day) for between 3 and 18months. We found that temporary hearing loss could be detected after 6 months of daily exposure, without leading to permanent hearing loss or to missing synaptic ribbons in cochlear hair cells. The degraded temporal representation of sounds in the auditory cortex after 18months of exposure was very different from the effects observed after only 3 months of exposure, suggesting that modifications to the neural code continue throughout a lifetime of exposure to noise.

Impact Assessment of Workers on Short Term Exposure within the Recommended Permissible Noise Exposure Limit (85 - 90 dBA)

As occupational safety and health become a focus in developing third world countries like the Philippines, research, test, and measurement were given investment to improve the status of health and safety. This study sought to determine the effect of 85 to 90 dBA exposure to workers in a controlled environment. Age, work experience, and gender were also assessed for possible correlation on the performance while exposed to different noise levels. One at a time, workers proceed to the audio isolation booth with observation window, controlled temperature, relative humidity, lightings, and noise level to complete three tasks namely abstract and logic test for 60 minutes, simplified mathematics test for 30 minutes, and set-up activity for 15 minutes. Each worker has to complete six sets of tests with a different continuous noise exposure level of 85 to 90 dBA. Observations of incidents inside the booth were also noted in the results. Workers perform best with a mean of 72% for 85 dBA in declining pattern to 38% performance for 90 dBA noise exposure for the Abstract and logic test. The same pattern was observed for a simplified mathematics test with the mean of 86.80% for 85 dB dropping to 64% for 90 dBA exposure while the actual set-up activity obtained 65% mean for worker completion when exposed to 85 dBA sliding to 35% for 90 dBA. In addition, the tallied health and safety issues raised by the workers and notes by the observers resulted in an increasing trend from 5% for 85 dBA, 11% for 86 to 88 dBA, 26% for 89 dBA, and 37% for 90 dBA. On the other hand, Pearson correlation confirms the negative correlation of noise level to abstract and logic, simple mathematics, and practical assembly set-up while noise level has a positive correlation with Health and Safety issues. Overall, if the 90 dBA noise level or higher is maintained in a specific workplace without any controls or interventions to lower down the noise level, the productivity and efficiency of workers will be low while their health and safety might be at risk.

Occupational Noise Reduction in CNC Striping Process

Occupational noise hearing loss with high level exposure is common occupational hazards. In CNC striping process, employee that exposed to high noise level for a long time as 8-hour contributes to hearing loss, create physical and psychological stress that reduce productivity. In this paper, CNC stripping process with high level noises are measured and reduced to the permissible noise exposure. First condition is all machines shutting down and second condition when all CNC machine under operations. For both conditions, noise exposures were measured to evaluate the noise problems and sources. After improvement made, the noise exposures were measured to evaluate the effectiveness of reduction. The initial average noise level at the first condition is 95.797 dB (A). After the pneumatic system with leakage was solved, the noise reduced to 55.517 dB (A). The average noise level at the second condition is 109.340 dB (A). After six machines were gathered at one area and cover that area with plastic curtain, the noise reduced to 95.209 dB (A). In conclusion, the noise level exposure in CNC striping machine is high and exceed the permissible noise exposure can be reduced to acceptable levels. The reduction of noise level in CNC striping processes enhanced productivity in the industry.

Assessment of noise-levels of generator-sets in seven cities of South-Southern Nigeria

Noise pollution has been shown to be a global health hazard and this could be aggravated by the use of noise-emitting generators. Therefore, this study aims to determine the Sound Pressure Levels Sound Power Levels as well as Noisiness of sixty different models with various Power-ratings from fourteen generator brands, commonly used in homes/offices in seven cities covering South-Southern Nigeria. The results obtained between January 2013–December 2015 showed that for nearly all generator brands, models and ratings, the values of were above the Permissible Noise Exposure Limits recommended by and of and respectively for daytime safe human exposure. Also, the ‘Wilcoxon Signed Ranks Test’ analyses showed that the three (3) alternative hypotheses , and are statistically-significant and should be accepted – further implying that: the decibel-ratings of majority of these generator-models are evidently hazardous.

Improvements of the Recovery Line of Waste Toner Cartridges on Environmental and Safety Performances

A physical recovery line had been constructed in plant for the increasing waste toner cartridges in previous work. However, with the production, severe lacks of the line emerged: (1) there was little proper technology of treating the collected toner; (2) strong noise was produced from the line and influenced the health of worker. For disposing toner properly, a new collected system of toner was developed. An air current separator (ACS) was designed to separate organic materials from inorganic materials of toner. Then, the separated organic materials can be incinerated and the inorganic materials can be dumped. Movement behaviors of toner particles in the ACS were analyzed, and the optimized operation parameter (13.5 m/s) of air current speed was obtained by theory analysis and experiments. For controlling the noise, noise levels emitted from the different process of the line were measured. The results indicated noise levels emitted from crusher (95.2 dB(A)) and agitator/magnetic separator (AMS, 91.9 dB(A)) were greater than the permissible noise exposure level of the Occupational Safety and Health Standards (90 dB(A)). The noise levels of other processes of the line were relatively safe. An acoustic hood was developed to reduce the noise levels of the crusher and the AMS. Then, the noise levels were both decreased to 67.6 dB(A). This paper provided important data for the environment on the industrialization of waste toner cartridges recovery.

Noise exposure limits and measurements for earphones

There are noise exposure concerns regarding the use of audio earphones and telephone receivers. The permissible noise exposure limits have been defined for the occupational environment for many years, for instance, the US Code of Federal Regulations, 29CFR1910.95, Occupational noise exposure and the Directive 2003/10/EC of European Parliament on Minimum Health and Safety Requirements. Those permissible noise exposure limits are defined for noise exposure in an ‘‘open-field’’ environment. An open-field environment is an environment where the noise sources are at a distance from a person’s ear. The sound or noise field can be a combination or any of a free field, or partially reflected, diffused, and reverberant fields. Nonetheless, the noise exposures from earphones are not in an open field. They are localized at or inside the user’s ear. Conventional open-field noise exposure measurement methods do not apply. During the last 15 years or so, a few different test methods for measuring noise exposure from earphone or telephone receivers were developed. The standards of ITU-T P.360, UL 60950-1, IEEE 269, and EN 50332 were developed mostly by the telephone industry. This presentation addresses the common permissible noise exposure limits, how to relate the limits to earphones, and how to measure them.

Acoustic noise analysis in echo planar imaging: multicenter trial and comparison with other pulse sequences

The purpose of this study was to evaluate acoustic noise in echo planar imaging (EPI) at various magnetic resonance imaging (MRI) centers and to compare EPI acoustic noise with that in other fast pulse sequences. We measured A-weighted root-mean-square sound pressure levels and peak impulse sound pressure levels for EPI, under the same conditions, in eleven clinical super-conducting MRI systems. We also compared sound pressure levels for the EPI and six different pulse sequences and analyzed the acoustic noise spectra. Sound pressure levels during the use of the EPI differed greatly among institutions. Moreover, sound pressure levels of the EPI were not significantly different from those of other fast pulse sequences and were within permissible noise exposure levels. In comparison to other fast sequences, the EPI had significantly greater acoustic noise in the high-octave band frequency.

Noise in the ICU.

The growing number of technical devices in ICUs makes noise exposure a major stressor. The purpose of this study was to assess noise levels during routine operation in our ICU. Our ICU is an open ward with four rooms, constructed in the 1960s. During the study period, 4 patients were in the controlled room and were treated by 4 nurses during the day and by 2 at night. A-weighted sound pressure levels (SPL) were measured continuously for 2 days and nights. Also measured were the alarms of various appliances. For gross overall evaluation it is customary to state the Leq, i.e. the energy-averaged level during measurement. The annoyance caused by noise depends more on rare events of high intensity. Therefore, the distribution of SPL values (Ln) over time was also analysed. SPL was roughly the same during the day and at night, with Leq between 60-65 dB(A) and peaks up to 96 dB(A). Most alarms reach an SPL of 60-70 dB(A), but some exceed 80 dB(A). During teaching rounds Leq exceeds 65 dB(A). During the day and at night SPL always surpasses the permissible noise exposure for 24 h of 45 db(A) recommended by the US Environmental Protection Agency. Alarms cause the most irritating noise. Hospital management should pay attention to internal noise, and SPL should be measured routinely.

Enviromental Improvement on Use of Farm Structures and Equipments Opinions of the workers about the working conditions in the rice processing plants

We examined the workers in the rice processing plants in order to determine the effects of noise pollution. This investigation consisted of a social survey and physical measurements. To summarize our interpretation, we can explain as follows:1) The predominant noise sources identified were the dryer and the huller in the rice processing plants. The proportion of the plants in which the noise level was higher than 90dB(A) to the worker's ear, is about from 50 to 60 percent.2) When the plants scale is smaller, the building is located in crowded areas. While the complaints of noise is not heard in sparsely populated areas, in 50 percent of the other plants, the inhabitants in the area lodge complaints.3) The workers pointed out two detrimental factors in their working enviroments. 70 percent complained of the dust and 21 percent complained of the noise. However a larger proportion of workers in the younger age level in large scale plants were more susceptible to noise than that of higher age levels.4) The majority of the workers stated the noise in the plants was higher than tractor and combine noise. Therefore, a control of noise in the plants is necessary in rice plants and agricultural machinery.5) As the predominants noise source in the plants, about half of the workers pointed out the huller and the dryer. The rate agreed very well with the values of physical measurements. As a result, it was clear that the workers accurately recongnized the noise source in the plants and its effects.6) The effect of the noise in the plants as compared with others such as super express noise and the rate of response to the noise shows lower values. But the effect of the noise in the plants on sleep and conversation are clear and the largest influence is seen in younger age level.7) The effects of noise in the plants on hearing in conversation begins at a comparatively low level with difficulty in sleeping and mental influence following. And at a high noise level physical influence is seen. Most of the workers reported a feeling that the noise exposure over long period had ill effects on their health.8) The workers know that there is a standard of the permissible noise exposure but few seem to actually realize the significance.9) From the results of Fig. 6 and 7, it may be necessary to restrict the permissible noise level in plants to 85dB(A).

Hearing loss due to continuous exposure to steady-state broad-band noise.

An analysis is made of data from a number of field investigations concerning the influence of steady-state broad-band noise on the hearing of workers, exposed to it continuously for eight hours a day. The results relate to exposure times ranging from 10 to 40 years and to noise with noise-rating numbers for 500 to 2000 Hz (NR) ranging from 75 to 98 or sound levels from 80 to 103 dBA. Noise-induced shifts of the median hearing levels as well as shifts indicated at the 90th, 75th, 25th, and 10th percentiles, were determined for seven frequencies between 500 and 8000 Hz as a function of exposure years and sound level. The variability in hearing levels associated with noise exposure was shown to be constant after ten exposure years and an increasing function of sound level at each frequency except 4000 Hz. At this frequency, the variance in hearing levels decreased with increasing sound level. The limit of permissible noise exposure, defined as the maximal level which did not cause measurable noise-induced shift in hearing levels of workers exposed to it irrespective of exposure years, was shown to be NR 75 or 80 dBA. An acknowledgment is made of the need for hearing-conservation measures given exposure conditions which exceed 80 dBA.

Occupational hearing loss. Recent guidelines and statutes of interest to the otolaryngologist.

AbstractRecent federal and state guidelines for permissible noise exposure levels have created renewed interest in the industrial noise problem. The purpose of this presentation is to review the provisions of the noise criteria, to discuss the role of the otologist, and to call attention to areas of inconsistency and conflict in the medical legal evaluation of hearing loss claims.

The Subjective Basis for Aircraft Noise Limitation

SummaryA brief review is given of the kinds of objective and subjective measurement required for systematic regulation of the aircraft noise around an airport, based on a maximum permissible noise exposure criterion. Some subjective factors are discussed and illustrated by test results.