Question

Pneumoconiosis is caused due to inhalation of which one of the following?

• A. Silica
• B. NO\(_x\)
• C. Lead
• D. Cadmium

Hint:

All pneumoconiosis diseases are linked to inhalation of inorganic mineral dusts.

Answer 1

The Correct Option is A

Pneumoconiosis refers to a group of lung diseases caused specifically by the inhalation of solid mineral dust that lodges in lung tissue and triggers scarring over time. NO\(_x\) is a gas, not a particulate, and its effect on the lungs is irritation rather than fibrotic dust disease. Lead and cadmium are both heavy metals whose toxicity mainly plays out elsewhere in the body, in the nervous system and kidneys respectively, once absorbed, rather than as a lung dust disease. Silica, however, is inhaled as fine mineral dust that becomes trapped in the alveoli and provokes a long-term fibrotic response, which is the textbook mechanism of pneumoconiosis, in this instance called silicosis.

Therefore, the correct answer is Silica.

Answer 2

Grouping these four substances by the organ system they primarily damage narrows this down quickly.

1. Silica: This is a mineral dust that specifically targets the lungs, becoming lodged in lung tissue and causing progressive fibrosis, exactly matching the disease category described in the question.
2. NO\(_x\): This gaseous pollutant causes airway irritation and inflammation rather than the particulate-driven fibrotic scarring associated with pneumoconiosis.
3. Lead: This heavy metal is absorbed into the bloodstream and mainly affects the nervous system and blood-forming tissue, not the lungs directly.
4. Cadmium: This heavy metal primarily damages the kidneys and, with long-term exposure, weakens bone, rather than scarring lung tissue.

Since pneumoconiosis is a lung-specific dust disease and only silica among these options is a mineral dust that directly damages lung tissue in this way, it is the correct cause.

Therefore, the correct answer is Silica.