High-frequency hearing risk of operators of industrial ultrasonic devices

Abstract

Sound and ultrasound emitted by industrial ultrasonic (Uls) devices exceed the known proposed hygienic limits, especially for frequencies 10-20 kHz. The consequence of this may be a negative influence of this energy on the auditory function in the high-frequency hearing range. To determine the hearing risk to Uls operators, an adequate method for testing the hearing threshold from 10-20 kHz has been developed. In order to get reference values, 189 non-exposed persons were tested. On this basis, the hearing thresholds of 55 operators for frequencies 500-20,000 Hz were evaluated. In addition to threshold elevations in the range 10-20 kHz, a decreasing number of subjects responding to stimuli at the highest audible frequencies was observed. The threshold shift at 10-20 kHz of subjects exposed to sound and ultrasound emitted by Uls-devices depends upon the physical parameters of the sound spectrum, time on the job and daily exposure time. No abnormalities were found in the hearing range 500-8000 Hz.

Are some people suffering as a result of increasing mass exposure of the public to ultrasound in air?

“…These conclusions were drawn by looking at averages of the cohort [114], whereas in a companion paper [115] Grezsik & Pluta returned to the factory they examined in 1983 [111] and tested again the 26 workers out of the original 55 who were still employed by the factory, using the same methods they employed in 1983. This enabled them to compare the effect of 3 years of additional industrial exposure on individuals, and they detected an additional hearing loss (over and above ageing) of 1 dB per year in the range 14-17 kHz for workers with prolonged exposure.…”

Effects of Ultrasonic Noise on the Human Body—A Bibliographic Review

“…A study of dentists using dental scalers (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42) showed that a short exposure to ultrasonic noise did not cause hearing loss at 0.5-8 kHz, except for a slight hearing impairment at 3 kHz [16]. However, in that study, hearing thresholds with the range of higher frequencies, i.e., 8-16 kHz, were not established for dentists.…”

“…Therefore, admissible values were determined at a level that does not eliminate hearing damage and subjective effects (fatigue, headache, nausea, tinnitus, vomiting, etc.) [40,41,42,43].…”

Assessment of Ultrasonic Noise Hazard in Workplaces Environment

“…In spite of relatively wide knowledge on the subject of ultrasonic noise sources and the ultrasonic noise itself appearing at the workplaces as well as of general conviction about its harmful interaction on the human body, the activity in the field of the assessment of the ultrasonic noise hazard on the working people is still not sufficient. The problems of ultrasonic noise are a subject of scientific and normalization interest in different places in the world (Grigoriewa, 1965;Acton, 1974;1975 Grzesik, Pluta, 1978;1983; 1986; Koton, 1986;1988;1999;2004) and among others, there in CIOP-PIB (Central Institute of Labour Protection -National Research Institute, Poland) procedures of hazard assessment and methods for evaluation of the ultrasonic noise on human body were performed (Pawlaczyk-Łuszczyńska et al, 2001a;2001b) as well as some normative establishments were elaborated (Polish Norms, 1986); Recently, however, they were not taken into account in the norm (Polish & ISO Norms, 2011) and formally they stopped to be in operation. Further and recent works continued in CIOP-PIB are important for elaboration of reliable procedures of ultrasonic noise hazard at workplaces and they should lead to current interest and to establish the adequate standards for the matter (Radosz, 2012a;2012b;Smagowska, 2012).…”