Environmental and occupational health
Scope
This domain tests exposure assessment, environmental health risks and the hierarchy of controls in workplaces.
Core rules
- Risk is hazard × exposure; a hazard is not a risk until people are exposed. Dose–response, timing and latency determine health effects.
- Key air pollutants are PM2.5, PM10, nitrogen dioxide, ozone, sulphur dioxide and carbon monoxide. WHO 2021 guidelines set annual PM2.5 at 5 µg/m³ and 24-hour at 15 µg/m³. Health effects include respiratory and cardiovascular disease and premature mortality.
- Safe water, sanitation and hygiene are core public health functions; water safety plans identify hazards from catchment to tap. Vector control, food hygiene and climate adaptation (heat plans) complete environmental health protection.
- The occupational hierarchy of controls is elimination, substitution, engineering controls, administrative controls and, last, personal protective equipment.
- Occupational exposure limits include time-weighted averages and short-term exposure limits. Noise action levels are 80 dB(A) for lower exposure action and 85 dB(A) for upper action; hearing protection is not a substitute for noise reduction.
- Risk assessment follows hazard identification, exposure assessment, risk characterisation and control, with review. EU Directive 89/391/EEC sets the general framework for worker safety. Environmental justice requires that disadvantaged communities are not disproportionately exposed.
Worked example
Construction workers cutting silica-containing concrete use dry cutting. The hazard is respirable crystalline silica; the risk includes silicosis and lung cancer. Applying the hierarchy: eliminate by prefabrication, substitute low-silica materials, engineer water suppression and local exhaust ventilation, administer rotation and training, and provide FFP3 respirators as the final layer with fit testing. The reasoning: PPE depends on correct use and fails silently, so it cannot be the primary control.
Traps
Do not start with PPE; do not confuse hazard with risk; do not treat an exposure limit as a safe boundary with no margin; do not ignore vulnerable groups such as pregnant workers and workers with pre-existing disease.