Occupational Health and Hygiene
What the examiner expects
Understand the main occupational health hazards: chemical (dusts, fumes, vapours, gases), physical (noise, vibration, heat, radiation), biological, ergonomic and psychosocial. Know the routes of entry - inhalation, ingestion, skin absorption, injection - and the difference between acute and chronic effects. Learn the principles of occupational hygiene: anticipation, recognition, evaluation, control of exposures. Know the meaning of exposure limits (OELs, TWA, STEL), the purpose of workplace monitoring and personal sampling, and the role of health surveillance in detecting early harm.
Traps
- Treating an OEL as a safe/unsafe boundary rather than a benchmark to stay well below.
- Confusing workplace monitoring (environment) with health surveillance (people).
- Missing that skin absorption and ingestion can matter as much as inhalation.
- Forgetting noise-induced hearing loss is irreversible; controls must be at source.
- Overlooking psychosocial risks as genuine occupational health hazards.
Worked example / rule of thumb
A worker is exposed to noise averaging 92 dB(A) over an 8-hour shift. Hazard: noise; effect: irreversible hearing damage. Controls in order: reduce at source (quieter equipment), isolate/enclose, limit exposure time, then hearing protection and audiometry. Rule of thumb: measure first, control at source, protect the person last, and verify with health surveillance.
Practical skills
Interpret monitoring results against OELs, explain the purpose of biological monitoring, and describe a health surveillance programme matched to the specific hazard.