Question 3 of 7: Airborne Contaminants and Chemical Health Effects

Question 3: Airborne Contaminants and Chemical Health Effects (20 marks: 7/7/6)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(i) Types of Airborne Contaminants

• Dusts (grinding), fumes (condensed vaporized metals), mists, smoke, gases, vapours, fibres (asbestos).

(ii) Health Effects of Chemicals

• Irritants, corrosives, asphyxiants (simple/chemical), sensitizers, systemic toxins (organ damage), carcinogens/mutagens/teratogens. Acute or chronic, local or systemic, dependent on toxicity, dose and route.

(iii) Main Routes of Entry

• Inhalation (most common/rapid), skin/eye absorption or contact, ingestion, injection. Controls target the route (ventilation/respirators, gloves/clothing, hygiene).

These contaminants matter because their physical form governs how deeply they penetrate the lungs and how they are controlled: fine fumes and respirable dust (roughly below 10 µm) reach the alveoli, whereas larger particles deposit in the upper airway; gases and vapours distribute by concentration. Inhalation dominates as a route because the lungs present a very large, thin, well-perfused surface directly to workplace air, so airborne exposure is assessed against permissible exposure limits and controlled first by ventilation and enclosure, and only lastly by respirators.