Evaluating worker vibration exposures using self-reported and direct observation estimates of exposure duration

Area of Science:

• Occupational Health
• Ergonomics
• Industrial Hygiene

Background:

• Accurate exposure time data is crucial for calculating average vibration exposure (A(8)) and conducting reliable risk assessments.
• Subjective methods like questionnaires may lead to significant overestimation of exposure times compared to objective measures.

Purpose of the Study:

• To compare objective (direct observation) and subjective (questionnaire, interviews) methods for collecting exposure time data for hand arm vibration (HAV) and whole-body vibration (WBV).
• To evaluate the impact of inaccurate exposure times on the calculation of average vibration exposure (A(8)).

Main Methods:

• Data collection via questionnaire surveys, daily worker interviews, and 8-hour direct workplace observations.
• Measurement of vibration magnitudes for various hand tools and vehicles.
• Calculation of daily vibration exposure estimates (A(8)) using observed, interviewed, and self-reported exposure times.

Main Results:

• Questionnaire self-reported exposure times were significantly higher (median 9.0x for HAV, 6.0x for WBV) than direct observations.
• Interview-reported times were more reliable than questionnaires (median 2.1x for HAV, 1.4x for WBV higher than observed).
• A(8) values calculated using questionnaire data were up to 66% (HAV) and 75% (WBV) greater than those using observed times.

Conclusions:

• Direct workplace observation and worker interviews are recommended over questionnaires for collecting exposure time data in variable work settings.
• Accurate exposure time assessment is vital for reliable occupational risk assessments related to vibration exposure.