ゴーカートインストラクターの動的なトラック環境における職業的騒音および振動リスク

This study evaluates occupational noise and vibration exposure among nine male go-kart instructors (mean age 25.7 years, mean work experience 6.3 years; 2-12 years) using objective measurements, predictive modelling, and subjective hearing assessments. Daily noise exposure (L_EX,8 h) ranged from 75.8 dB to 82.3 dB, with peak levels reaching 109.3 dB. Regression analysis showed that operating more than nine go-karts simultaneously could exceed the 85 dB regulatory threshold, predicting noise levels up to 92.7 dB at full capacity. Whole-body vibration (WBV) exceeded short-term exposure limits in two of four cases (max 3.26 m/s²), while hand-arm vibration (HAV) surpassed limits in three cases, reaching 14.23 m/s². The average score on the Amsterdam Inventory for Auditory Disability and Handicap (AIADH) was 68.1, indicating mild perceived hearing difficulties. Strong negative correlations were found between AIADH scores and both age and work experience. Our findings reveal hidden risks in this recreational occupational setting and underscore the need for more nuanced exposure assessment and preventive measures in non-industrial sectors.