Measuring occupational exposure to very high frequencies noise: Assessing measurement variability under controlled conditions

Many occupational sectors are exposed to noise from very high audible frequencies (VHF) or low-frequency ultrasound (LFUS). Despite numerous studies on VHF/LFUS exposure, the question of the impact of several parameters in the on-site measurement protocol on the representativeness of the measurement remains open. Laboratory measurements were carried out to assess the variability of exposure measurements under controlled conditions as a function of the presence/absence of the microphone’s protection grid, the location of the microphone (shoulder, ear entrance, etc.), the side of the dummy where the microphone is located, and the frequency and angle of the source. Particular attention has been paid to the possibility of positioning the microphone at temple level, thanks to a specific mounting system adapted to on-site use.