Effect of noise and hand-transmitted vibration exposure on hearing and equilibrium under a simulated work environment with building tools

Construction workers are mainly exposed to hand-arm vibration (HAV) and/or noise caused by vibrating hand tools in the working environment. The present study aimed to investigate the effects of coexposure to HAV and noise on workers' hearing loss and body balance. Forty construction workers were exposed to HAV (10 m/s2 rms, 31.5 Hz) and/or typical construction noise (90 dBA) in three simulated experiment scenarios with the typical vibrating hand-held tool for 30 minutes in three days. The temporary hearing threshold shifts from 1000 to 8000 Hz and the body balance in the anterior-posterior (A/P) and medial-lateral (M/L) directions were determined before and after each short-term exposure scenario. The results showed separate noise exposure at all frequencies except for 1000 Hz could significantly affect hearing threshold levels. Separate exposure to HAV can not lead to remarkable effects on hearing loss, however, it can synergistically increase the dominant effect of noise on hearing loss. Also, the affected frequency range in concurrent exposure has been more than in separate noise exposure. The separate effects of exposure to HAV and noise on the subjects’ body balance were not statistically significant while these effects became significant in concurrent exposure. Based on the estimated effect sizes, noise could synergistically increase the observed effect of HAV on body balance in both axes. It is observed that synergetic interaction between HAV and noise on hearing and body balance performance. Concurrent exposure to noise and vibration is inevitable when working with construction tools, hence, it is recommended that this evidence is considered for setting threshold or action limit values.