Occupational Health and Industrial Hygiene
Core concepts
Industrial hygiene is the anticipation, recognition, evaluation, and control of workplace health hazards. Candidates must know the exposure routes (inhalation, skin absorption, ingestion, injection) and the main agent types: chemical, physical (noise, vibration, heat, radiation), biological, and ergonomic.
Evaluation and control
Understand exposure assessment: sampling strategy, personal versus area sampling, and comparison with occupational exposure limits. Know that exposure limits vary by jurisdiction and that time-weighted averages account for exposure duration. For noise, know the concept of an 8-hour average and the need for hearing protection at action levels. For chemicals, know that safety data sheets and ventilation are key controls.
Traps in questions
- Confusing area sampling with personal exposure.
- Ignoring skin absorption for chemicals that pass through skin.
- Assuming a single sample represents a full shift.
- Forgetting that exposure limits are not bright lines of safety.
Rule of thumb
Match the sampling method to the route and the duration. If a substance can be absorbed through skin, air sampling alone underestimates exposure.
Worked example
A worker uses a solvent for two hours. Personal air sampling shows a level below the 8-hour limit, but the solvent is a skin irritant and absorbed through skin. The correct conclusion is that air sampling is insufficient; add gloves, ventilation, and skin protection.