Méthode de mesure individuelle de l'exposition sonore effective intra-auriculaire en milieu de travail

Abstract

Many workers are exposed daily to noise levels that could affect their hearing. As a result, it is imperative that sound exposure be monitored to identify and evaluate corrective solutions to adequately protect workers. Current conventional sound exposure measurement methods and technologies are generally unable to reliably account for the noise variations that workers may experience in their environment, nor for the attenuation provided by hearing protectors when worn. To overcome these issues, in-ear noise dosimeters (IEND) have emerged in recent years, offering the advantage of continuous measurements directly inside the earcanal, even beneath hearing protectors. Nevertheless, the use of IENDs is still subject to several problems. This manuscript-based thesis constitutes a study in three main stages, each of which studies one of these problems. First, the results of loudness balance experiments performed on 18 human participants suggest that hearing sensitivity is unaffected by changes in the acoustic load applied to the earcanal, thus supporting the argument that the risk of hearing damage induced by a given sound pressure at the eardrum is independent of whether or not hearing protectors are worn. Next, methods and instrumentation were developed to allow IENDs to be indivually calibrated in the field. A series of experiments involving human participants showed that these methods, as well as the prototypes used, could serve to determine, for the first time ever, the individual acoustic corrections needed for in-ear noise dosimetry measurements performed in the open ear or under an earplug or earmuff. Finally, these same prototypes were used for the development of an approach aimed at detecting, and excluding, if necessary, the noise disturbances induced by an individual wearing an IEND. This approach, tested in the laboratory on 14 human participants, proved particularly effective in the case of measurements performed under an earplug. Overall, this thesis presents the methods, tools and knowledge developed to allow the individual measurement of the effective in-ear noise exposure in the workplace. By significantly reducing the number of constraints associated with IENDs, such work should have significant implications for the prevention of occupational hearing loss. Results show that the advances made are particularly conducive to measurements performed under an earplug, but may eventually cover a wide range of noise conditions and hearing protection requirements.

Date	29 May 2019
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Jérémie Voix (Supervisor) & Hugues Nélisse (Co-supervisor)