Dust aerosols.
Dust aerosols are airborne solid particles that can be inhaled by workers, originating from industrial processes such as mining, milling, construction, metallurgy, and chemical production. Their size, concentration, and chemical composition determine health risks.
II. Hygienic Characteristics
- 1. Particle size:
- >10 µm: Mostly settle in the upper respiratory tract.
- 5–10 µm: Can reach bronchi.
- <5 µm (respirable fraction): Penetrate alveoli → greatest health risk.
- 2. Concentration limits (occupational exposure limits, OELs):
- Vary by dust type (e.g., silica, coal, asbestos).
- General dust limit: 2–10 mg/m³ (depending on type).
- 3. Composition:
- Inorganic dust: silica, metal oxides → pulmonary fibrosis, cancer.
- Organic dust: flour, cotton, wood → allergic reactions, asthma.
III. Biological Effects
- 1. Respiratory system:
- Irritation of mucous membranes, chronic bronchitis, pneumoconiosis, asthma.
- 2. Systemic effects:
- Some metals (lead, arsenic) → systemic toxicity affecting kidneys, liver, and nervous system.
- 3. Carcinogenic potential:
- Silica, asbestos, certain metals → increased risk of lung cancer.
IV. Prevention & Control Measures
- 1. Engineering controls:
- Local exhaust ventilation, wet methods to suppress dust.
- Isolation of dusty processes.
- 2. Work organization:
- Limit exposure time, job rotation.
- 3. Personal protective equipment (PPE):
- Respirators or masks, protective clothing.
- 4. Hygienic monitoring:
- Regular air sampling and dust concentration assessment.
- 5. Medical surveillance:
- Periodic health checks for early detection of dust-related illnesses.