Analysis of the functional and acoustical comfort of earplugs experienced by a group of workers in Canadian companies and identification of the influencing variables

• Person-related characteristics dominate earplug functional and acoustical comfort. • Earcanal morphology significantly impacts experienced comfort. • Prior HPD experience linked to less favorable comfort evaluations. • Handedness, ear asymmetry, and hearing loss influence earplug comfort outcomes. Earplugs are essential for hearing protection in noisy workplaces, but their effectiveness depends heavily on user comfort, which influences proper and consistent use. This study explores functional and acoustical comfort experienced by 173 workers across Canadian companies, each testing different ’disposable or reusable’ earplug models over seven weeks. Comfort is assessed using detailed questionnaires covering six subdimensions: ease of insertion and removal, noise protection, impact on work, and discomfort related to internal and external noise perception. Linear mixed-effects models are applied within a triad framework encompassing person-, earplug-, and environment-related characteristics in order to identify those with a significant influence on functional and acoustical comfort. Results show that person-related variables are the most influential. Handedness, hearing loss, and prior HPD experience significantly impact comfort, with left-handed participants reporting greater insertion and removal discomfort—possibly due to earcanal asymmetry and dexterity differences. Several earcanal morphological features also play a role, including isoperimetric ratios, circumference at multiple cross-sections, conicity, and length. Only a few earplug-specific characteristics influence comfort outcomes. Foam expansion time is linked to reduced acoustical discomfort associated with the perception of internal sounds, while stem presence improves insertion ease. Environmental factors do not have significant effects. In the longer term, these findings call for a rethinking of the design and selection of ’disposable or reusable’ earplugs, primarily based on earcanal morphology and users’ past experience. The study also underscores the need for improved objective metrics to assess comfort and supports the development of more personalized hearing protection solutions.