Inhalation is the process by which airborne substances such as gases, vapors, fumes, dust, aerosols, or mists enter the body through the respiratory system, i.e nose, throat, and lungs, where they may be absorbed into the bloodstream.
The respiratory system consists of the nose, nasal passages, mouth, epiglottis, pharynx, larynx, trachea, bronchi, and alveoli. Air enters the body through the nose or mouth and travels down to the alveoli, where gas exchange with the blood occurs.
Explanation
Inhalation is a critical physiological process that allows oxygen to enter the body for respiration. However, in occupational health and safety, inhalation is also a primary route of exposure to hazardous substances in the workplace. Harmful airborne contaminants—such as chemical fumes, toxic dust, mold spores, or biological agents—can be inhaled, potentially leading to acute or chronic health effects, including respiratory diseases, poisoning, or systemic toxicity.
Upon inhalation, these contaminants travel deep into the lungs. The lungs are designed for efficient gas exchange, with a very large surface area and a rich blood supply, which unfortunately also makes them highly effective at absorbing toxic chemicals into the bloodstream.
When a substance is aerosolized into particles (dusts, fumes, mists) or exists as a vapor or gas, it can be easily breathed in.
Once inhaled, harmful agents can either:
- Stay in the respiratory system (causing irritation, asthma, or lung disease), or
- Pass into the bloodstream (leading to systemic effects such as poisoning).
The degree of harm depends on factors such as:
- Concentration of the substance in the air
- Duration and frequency of exposure
- Particle size (smaller particles can penetrate deeper into the lungs)
- Solubility and toxicity of the substance
Inhalation hazards are particularly concerning in construction, manufacturing, mining, healthcare, and chemical industries, where workers may be exposed to dusts, vapors, fumes, or infectious aerosols.
Examples
- Silica dust: Workers cutting or grinding concrete may inhale fine crystalline silica dust, leading to silicosis or chronic obstructive pulmonary disease (COPD).
- Asbestos fibers: Inhalation of asbestos fibers can cause serious long-term illnesses, including asbestosis, lung cancer, and mesothelioma.
- Chemical vapors: Breathing in solvent vapors (e.g., from paints or adhesives) may cause dizziness, headaches, or long-term neurological effects.