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1

The Hearing Threshold of Employees Exposed to Noise Generated by the Low-Frequency Ultrasonic Welding Devices

Dudarewicz A., Zaborowski K., Rutkowska-Kaczmarek P., Zamojska-Daniszewska M., Śliwińska-Kowalska M., Zamysłowska-Szmytke E., Pawlaczyk-Łuszczyńska M.

Archives of Acoustics

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2017

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Vol. 42, No. 2

199--205

EN

The aim of the study was to assess the hearing threshold levels (HTLs) in employees exposed to noise generated by low-frequency ultrasonic technological equipment in comparison with the HTLs of workers exposed to audible noise at the similar A-weighted equivalent-continuous sound pressure level. The study includes measurements of ultrasonic and audible noise at workplaces and hearing tests, i.e. conventional pure-tone audiometry and extended high-frequency audiometry. The study group comprised 90 workers, aged 41.4 ± 10.0 years (mean±SD), exposed for 17.3 ± 9.8 years to noise generated by ultrasonic devices at mean daily noise exposure level (‹LEX,8h›) of 80.6 ± 2.9 dB. The reference group consists of 156 subjects, exposed to industrial noise (without ultrasonic components) at similar A-weighted equivalent-continuous sound pressure level (‹LEX,8h› = 81.8 ± 2.7 dB), adjusted according to age (39.8 ± 7.7 years), gender and job seniority (14.0 ± 7.0 years). This group was selected from database collected in the Nofer Institute of Occupational Medicine. Audiometric hearing threshold levels in the frequency range of 0.5–6 kHz were similar in both groups, but in the frequency range of 8–12.5 kHz they were higher in the group of employees exposed to ultrasonic noise. The findings suggest that differences in the hearing threshold (at high frequencies) in analyzed groups may be due to differences in spectral composition of noise and show the need to continue the undertaken studies.

2

The Influence of Selected Risk Factors on the Hearing Threshold Level of Noise Exposed Employees

Dudarewicz A., Toppila E., Pawlaczyk-Łuszczyńska M., Śliwińska-Kowalska M.

Archives of Acoustics

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2010

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Vol. 35, No. 3

371-382

EN

The aim of the study was to evaluate the combined effect of noise exposure and additional risk factors on permanent hearing threshold shift. Three additional risk factors were: exposure to organic solvents, smoking and elevated blood pressure. The data on exposure and health status of employees were collected in 24 factories. The study group comprised of 3741 noise male exposed workers of: mean age 39§8 years, mean tenure 16§7 years and LEX;8h = 86 § 5 dB. For each subject, hearing level was measured with pure tone audiometry, blood pressure and noise exposure were assessed from the records of local occupational health care and obligatory noise measurements performed by employers. Smoking and solvent exposure were assessed with questionnaire. The study group was divided into subgroups with respect to the considered risk factors. In the analysis, the distribution of hearing level of each subgroup was compared to the predicted one which the standard calculation method described in ISO 1999:1990. For each of the considered risk factors, the difference between measured and calculated hearing level distribution was used to establish, by the least square method, a noise dose related correction square function for the standard method. The considered risk factors: solvent exposure, smoking and elevated blood pressure combined with noise exposure, may increase degree of hearing loss.

3

Hearing Ability in Orchestral Musicians

Pawlaczyk-Łuszczyńska M., Dudarewicz A., Zamojska M., Śliwińska-Kowalska M.

Archives of Acoustics

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2010

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Vol. 35, No. 4

579-594

EN

Pure-tone audiometry (PTA) and transient-evoked otoacoustic emissions (TEOAEs) were determined in 57 classical orchestral musicians along with a questionnaire inquiry using a modified Amsterdam Inventory for Auditory Disability and Handicap ((m)AIADH). Data on musicians’ working experience and sound pressure levels produced by various groups of instruments were also collected. Measured hearing threshold levels (HTLs) were compared with the theoretical predictions calculated according to ISO 1999:1990. High frequency notched audiograms typical for noise-induced hearing loss were found in 28% of the subjects. PTA and TEOAE consistently showed a tendency toward better hearing in females vs. males, younger vs. older subjects, and lower- vs. higher-exposed to orchestral noise subjects. Audiometric HTLs were better than theoretical predictions in the frequency range of 2000–4000 Hz. The (m)AIADH scores indicated some hearing difficulties in relation to intelligibility in noisy environment in 26% of the players. Our results indicated a need to implement a hearing conservation program for this professional group.

4

Theoretical Predictions and Actual Hearing Threshold Levels in Workers Exposed to Ultrasonic Noise of Impulsive Character—A Pilot Study

Pawlaczyk-Łuszczyńska M., Dudarewicz A., Śliwińska-Kowalska M.

International Journal of Occupational Safety and Ergonomics

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2007

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Vol. 13, No. 4

409–-418

EN

Results of standard pure-tone audiom etry (PTA) were collected from 25 workers, mainly females, aged 23–58 years, exposed for 2–13 years to ultrasonic noise emitted by ultrasonic welders. Hearing tests were completed by evaluation of exposure to ultrasonic noise. The subjects’ actual audiometric hearing threshold levels (HTLs) were compared with theoretical predictions calculated according to ISO 1999:1990. In 60% of cases sound pressure levels in the 10–40 kHz 1/3-octave bands at workstands exceeded Polish exposure limits for ultrasonic noise. Our comparison of predicted and measured HTLs suggests that the ISO 1999:1990 method, intended for audible noise, might also make it possible to predict reliably permanent hearing loss (in the 2 000–6 000 Hz frequency range) after exposure to ultrasonic noise. No significant progress of hearing impairment (assessed using PTA) in the operators of ultrasonic welders was noted. Nevertheless, further studies on the hearing status of workers exposed to ultrasonic noise are needed.

5

Proposals of exposure criteria for the assessment of low frequency noise at workplaces in industrial control rooms and office-like areas

Pawlaczyk-Łuszczyńska M., Dudarewicz A., Śliwińska-Kowalska M.

Archives of Acoustics

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2007

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Vol. 32, No. 2

303-312

EN

The aim of the study was to recommend methods for assessing low frequency noise (LFN) in the occupational environment to prevent annoyance and its effects on work performance. Three different evaluating methods and corresponding admissible values were proposed: (i) method I - frequency analysis in 1/3-octave bands 10-250 Hz, (ii) method II - consisting in 1/3-octave band measurements and determination of low frequency equivalent-continuous A-weighted sound pressure level (SPL) in the frequency range 10-250 Hz, and (iii) method III - based on equivalent-continuous A-weighted SPL corrected due to the presence of low frequencies and tonal character of LFN. Separate noise limits were recommended for workplaces in the control rooms and office-like areas. The proposed criteria were verified in the field study on subjective noise annoyance rating. The subjects, 35 male workers, employed in the industrial control rooms, aged 40.1±7.2 years, exposed to LFN at A-weighted SPL of 48-61 dB, were asked to rate noise annoyance at their workplace using a 100-score graphical rating scale. Noise conditions in the control rooms were evaluated according to proposed assessment criteria. The subjective ratings of LFNs were compared to objective results from various assessing methods. The relations between annoyance and excesses of proposed limits were analyzed using Pearson correlation coefficient (r). Linear relationships between the subjective ratings and results from all proposed exposure criteria were observed (0.550≤r≤0.673, p<0.001). However, the highest correlation coefficient was found for method II (r=0.673).

6

Hearing loss in workers exposed to different type of noise

Zamysłowska-Szmytke E., Kotyło P., Bąk M., Fuente A., Śliwińska-Kowalska M.

Archives of Acoustics

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2007

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Vol. 32, No. 2

399-404

EN

It's well documented that noise damages peripheral part of the auditory tract (cochlea). Only few investigations were performed to assess central hearing disturbances caused by noise on animal. The aim of the study was to evaluate the site of hearing damage in 2 groups of individuals exposed to different types of noise. First group consisted of 62 dockyard workers exposed to impulsive noise with co-exposure to hand-arm vibration while second group included 76 bottle glass factory workers exposed to continuous steady-state noise. Results were referred to 86 control subjects exposed neither to noise nor vibrations. Pure-tone audiometry, immitance audiometry, Auditory Brainstem Response (ABR) and cognitive-event relate auditory evoked potentials (wave P-300) were performed in all subjects. Audiometric results revealed the poorest hearing level in dockyard workers among all groups. The bottle factory workers had also significant hearing impairment at high frequencies as compared to controls. Although the wave V at the ABR was prolonged in the dockyard workers this change could reflect sensorineural hearing thresholds shift and retrocochlear damage. The latency of P-300 wave was prolonged in dockyard workers exclusively suggesting a cortical effect of exposure to impulsive noise. Conclusions. Exposure to high level impulsive noise in combination with hand-arm vibration may cause hearing deficit greater than expected. Abnormalities involve peripheral and central auditory system. More observations are necessary to confirm these findings.

7

An optimal method of assessment the individual susceptibility to noise-induced hearing loss

Dudarewicz A., Pawlaczyk-Łuszczyńska M., Śliwińska-Kowalska M.

Archives of Acoustics

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2007

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Vol. 32, No. 2

241-250

EN

The aim of the investigation was to compare different methods of subject classification regarding susceptibility to noise induced hearing loss in group of 949 workers of power plant. In the first two methods, simple and accurate the classification was performed according international reference standard ISO 1999:1990. In the tree other methods the entire group of workers was divided into subgroups to obtain similar distribution of age, time of employment and level of noise exposure in the susceptible and resistant group. In the first two classifications the susceptible group was significantly younger then resistant group, had shorter time of employment and lower level of noise exposure. This findings are in line with the definition of increased vulnerability to noise inducted hearing loss. Additionally, an excellent separation between hearing thresholds (HTs) of the susceptible and the resistant group was achieved. All three other methods resulted in worse separation of HTs between susceptible and resistant group of subjects. Subjects pre-selection deteriorates the reliability of workers' dichotomization into noise-susceptible and noise resistant groups.

8

Two methods of vibration perception assessing in workers exposed to hand-arm vibration

Zamysłowska-Szmytke E., Szymczak W., Śliwińska-Kowalska M.

Archives of Acoustics

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2004

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Vol. 29, no. 2

309-315

EN

It is known that vibration perception could be influenced by the device parameters and technique of measurement. The influence of confounding factors like age, weight and height on VPTs values was assessed in previous analyses in non-exposed subjects. The aim of present study was to compare the results of two techniques of vibrotactile thresholds measurement in workers exposed to hand-arm vibration. Two methods of vibration perception assessment were compared in 124 workers (21-62 years old, 1-40 years of employment) exposed mainly to hand-arm vibration during the work as: chain saw operator, pneumatic hammers operators, metal grinders, fitters, dentist technician. One method (named "standard method") has been used in Poland so far; the second one (named "according to ISO method") was established on the base of ISO Standard 13091-1-2001. The methods differed not only in technical parameters of stimuli but also in the way of normative values evaluation. In standard method there were no individual features or habits included. The results of investigation revealed that age and weight play the important role in interpretation of tests results, both in standard and according to ISO method. Moreover, standard method measurements seem to overestimate the number of subjects with recognized vibration sense abnormalities. In both methods exposure to vibration mostly could be revealed by stimuli at frequencies of 125 and 250 Hz.

9

Influence of low frequency noise on cognitive performance tasks

Pawlaczyk-Łuszczyńska M., Dudarewicz A., Waszkowska M., Szymczak W., Śliwińska-Kowalska M.

Archives of Acoustics

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2004

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Vol. 29, no. 2

191-203

EN

To study the influence of low frequency noise (LFN) on cognitive performance tasks, 96 subjects, categorised in terms of sensitivity to LFN, worked with four standardised psychological tests during exposure to LFN or broadband noise without dominant low frequency content (reference noise) at a level of 50 dB(A). It was found that the test results were influenced by exposure and/or noise sensitivity. Regardless of sensitivity to noise, poorer results in the LFN (compared to reference noise conditions) were noted in the Comparing of Names Test (a tendency to more erroneous responses). High-sensitive subjects achieved poorer results than others during exposure to LFN in the Stroop Colour-Word Test (a significant interaction between noise and noise sensitivity in case of reading interference) and in the Continuous Attention Test (a tendency to more erroneous reactions). These findings suggest that LFN at moderate levels could adversely influence cognitive performance tasks and subjects high-sensitive to LFN may be at highest risk.

10

Does low frequency noise affect human mental performance?

Pawlaczyk-Łuszczyńska M., Dudarewicz A., Waszkowska M., Szymczak W., Kameduła M., Śliwińska-Kowalska M.

Archives of Acoustics

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2004

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Vol. 29, no. 2

205-218

EN

To study the influence of low frequency noise (LFN) on mental performance and subjective well-being, 192 male subjects, categorised in terms of sensitivity to noise in general, and to LFN in particular, worked with four standardised psychological tests. Three different acoustic conditions were used in the experiment: the background laboratory noise, LFN, and the broadband noise without dominant low frequency content (reference noise) at a level of 50 dB(A). The influence of exposure and/or noise sensitivity on the tests' results or their interaction were found in three of the four performed tests. Poorer results in the LFN (compared to other noise conditions) were observed in person classified as high-sensitive to noise in general and low-sensitive to LFN in the Signal Detection Test (more erroneous responses). The annoyance of LFN and reference noise was rated higher than that of the background noise. Subjects high-sensitive to noise in general reported the highest annoyance due to LFN. In conclusion, LFN at moderate level could be perceived as annoying and adversely affecting attention and visual perception, particularly in subjects high-sensitive to noise.

11

Hałas ultradźwiękowy : procedura pomiarowa

Pawlaczyk-Łuszczyńska M., Koton J., Śliwińska-Kowalska M., Augustyńska D., Kameduła M.

Podstawy i Metody Oceny Środowiska Pracy

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2001

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Nr 2 (28)

89--95

12

Hałas infradźwiękowy : dokumentacja proponowanych wartości dopuszczalnych poziomów narażenia zawodowego

Pawlaczyk-Łuszczyńska M., Augustyńska D., Kaczmarska-Kozłowska A., Śliwińska-Kowalska M., Kameduła M.

Podstawy i Metody Oceny Środowiska Pracy

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2001

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Nr 2 (28)

5--45

PL

Infradźwiękami przyjęto nazywać dźwięki lub hałas, którego widmo jest głównie zawarte w paśmie częstotliwości od 1 Hz do 20 Hz (ISO 7196). Z kolei hałas infradźwiękowy to hałas, w którego widmie występują składowe o częstotliwościach infradźwiękowych i niskich słyszalnych do 50 Hz (PN-86/N-01338). Źródłem hałasu infradźwiękowego w środowisku pracy są środki transportu oraz niektóre maszyny i urządzenia przemysłowe, w tym sprężarki tłokowe, pompy próżniowe, dmuchawy, piece hutnicze, młoty kuźnicze, kraty wstrząsowe, formierki maszynowe, urządzenia energetyczne elektrowni cieplnych (młyny, kominy, kotły i wentylatory kotłowe), wentylatory przemysłowe, maszyny drogowe, silniki odrzutowe testowane w hamowniach oraz urządzenia młynów zbożowych (przesiewacze zbożowe). Poziomy ciśnienia akustycznego (w pasmach oktawowych o częstotliwościach środkowych 4 -r 31,5 Hz), występujące zwykle na stanowiskach pracy związanych z wymienionymi maszynami, wahająsię w granicach od 80 dB do 120 dB. Dominującym skutkiem ekspozycji zawodowej na infradźwięki jest ich działanie uciążliwe, występujące już przy niewielkich przekroczeniach progu słyszenia, przejawiające się subiektywnie odczuwanymi stanami nadmiernego zmęczenia, dyskomfortu, senności oraz zaburzeniami sprawności psychomotorycznej i funkcji fizjologicznych. Obowiązujące obecnie wartości dopuszczalne hałasu infradźwiękowego2' nie są powiązane z progami percepcji słuchowej infradźwięków i nie odpowiadają wynikom badań doświadczalnych dotyczących subiektywnej oceny uciążliwości infradźwięków (krzywa G wg ISO 7196:1995). Propozycje nowych wartości dopuszczalnych hałasu infradźwiękowego uwzględniają obecny stan wiedzy na temat skutków oddziaływania, stosowane w innych krajach (a w szczególności w Szwecji i USA) kryteria oceny, wytyczne zawarte w normach międzynarodowych oraz własne wyniki pomiarów hałasu w środowisku pracy. Jako wartości dopuszczalne ze względu na ochronę zdrowia ogółu pracowników (wartości NDN) zaproponowano: równoważny poziom ciśnienia akustycznego skorygowany charakterystyką częstotliwościową G, odniesiony do 8-godzinnego dnia pracy lub tygodnia pracy, równy 102 dB (wyjątkowo w przypadku oddziaływania hałasu infradźwiękowego na organizm człowieka w sposób nierównomierny w poszczególnych dniach w tygodniu); szczytowy nieskorygowany poziom ciśnienia akustycznego równy 145 dB. Jako wartości dopuszczalne w odniesieniu do stanowisk pracy dla grup o szczególnej wrażliwości (kobiety ciężarne, osoby młodociane) zaproponowano: równoważny poziom ciśnienia akustycznego skorygowany charakterystyką częstotliwościową G, odniesiony do 8-godzinnego dnia pracy, równy 86 dB; szczytowy nieskorygowany poziom ciśnienia akustycznego równy 145 dB.

EN

Infrasound is assumed to be sound or noise whose frequency spectrum lies mainly in the range from 1 Hz to 20 Hz (ISO 7196:1995), whereas the "infrasonic noise" is referred to as the broadband noise containing infrasonic frequencies and low audible frequencies under 50 Hz. In the working environment the infrasonic noise is generated by some industrial machinery and appliances including piston compressors, vacuum pumps, blast furnace blowers, blast-furnaces (arc furnaces, oxygen convectors), forge hammers, vibrating grates, power moulding machines, electric power station devices (chimneys, ball and beater mills, power boilers and power boiler fans), industrial fans, road making devices (road rollers), jet engines and flour-mill devices (especially flour vibrating screens). Another important source of infrasonic noise are the means of transport. The sound pressure levels (4 4-31.5 Hz 1/1-octave bands) at workposts involving the use of such machinery usually fall within the range of 80 4-120 dB. The predominant effect of exposure to infrasound in the occupational setting is the discomfort and annoyance experienced by exposed workers. This effect occurs at infrasound levels slightly exceeding the hearing threshold. It is manifested mainly as the subjective perception of fatigue, drowsiness and impaired psychomotor performance and physiological functions. The admissible values for infrasonic noise which are currently in force in Poland are not related to the hearing threshold of infrasound and they do not correspond with the results of experimental studies on subjective annoyance rating of infrasound (G-weighting curve according to ISO 7196:1995). The proposals of new limit values for infrasonic noise take into consideration the state-of-the- -art knowledge on'the effects of infrasound on humans, the criteria for infrasound exposure applied in other countries (especially in Sweden and USA), the respective international standards and the results of own infrasonic noise measurements performed under conditions of occupational exposure. The proposed health-based hygienic standards for occupational exposure to infrasonic noise are as follows: 102 dB - for the equivalent G-weighted sound pressure level normalised to a nominal 8-hour workday or 40-hour working week 145 dB - for the unweighted peak sound pressure level. The following values have been proposed as exposure limits for workers at particular risk, i.e. pregnant women and juveniles: 86 dB - for the equivalent continuous G-weighted sound pressure level normalised over a nominal 8-hour workday 145 dB - for the unweighted peak sound pressure level.