How Airborne Hazards Harm the Body
Particles, gases, vapours and oxygen deficiency, and why size and timing matter.
11 min
Activities: 0 of 2
An adult breathes thousands of litres of air during a work shift. Anything in that air can reach the nose, throat and lungs, and some substances pass from the lungs into the blood. Respiratory protective equipment (RPE) exists because some workplaces cannot make the air clean enough. To choose and use it well, you first need to know what is in the air and how it causes harm.
Four kinds of breathing hazard
Dusts, fibres, fumes and mists. Dust comes from cutting, grinding and handling powders. Fume is very fine particles formed when metal is heated, as in welding. Mist is tiny liquid droplets from spraying or cutting fluids.
Why particle size matters
The nose and upper airways trap larger particles. Very small particles, called the respirable fraction, travel deep into the lungs where the body cannot easily clear them. These are often invisible. A workshop can look clean and still contain harmful respirable dust, such as crystalline silica from cutting stone or concrete.
Acute and chronic effects
Acute effects happen quickly after a high exposure: irritation, choking, unconsciousness, death. Chronic effects develop over months or years of lower exposure: lung scarring, asthma, cancer. Chronic disease is often found long after the work, when nothing can be done.
Match the hazard to its type
- Welding smoke from steel
- Solvent evaporating from paint
- Hydrogen sulphide in a sewer
- Nitrogen-purged vessel
A workshop looks clean, but workers cut stone all day. What is the main breathing concern?