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

Step 1: Understanding pneumoconiosis.
Pneumoconiosis is a group of occupational lung diseases caused by long-term inhalation of mineral dust particles.
Step 2: Common causative agents.
Silica dust causes silicosis, coal dust causes coal workers’ pneumoconiosis, and asbestos causes asbestosis.
Step 3: Analyzing the options.
(A) Correct, inhalation of silica dust leads to silicosis, a type of pneumoconiosis.
(B) Incorrect, NO\(_x\) causes respiratory irritation but not pneumoconiosis.
(C) Incorrect, lead causes systemic toxicity, not lung fibrosis.
(D) Incorrect, cadmium affects kidneys and bones primarily.
Step 4: Conclusion.
Pneumoconiosis is caused due to inhalation of silica dust.

Answer 2

Pneumoconiosis is defined by what happens physically inside the lungs after long-term dust inhalation, so tracing that mechanism for each option is the most reliable way to identify the responsible substance.

1. Silica: Fine silica dust particles, small enough to reach deep into the alveoli, are engulfed by lung macrophages that then die and release enzymes triggering a fibrotic scarring response around the trapped particles; this progressive scarring of lung tissue is precisely the disease process defined as pneumoconiosis, in this case specifically silicosis.
2. NO\(_x\): Nitrogen oxides are gases that cause irritation and inflammation of the respiratory airways and can contribute to conditions like bronchitis, but they do not cause the particulate-driven fibrotic scarring that defines pneumoconiosis.
3. Lead: Lead exposure is systemic, affecting the nervous system, blood, and kidneys after being absorbed into the bloodstream, rather than lodging in and scarring lung tissue.
4. Cadmium: Cadmium toxicity primarily targets the kidneys and, over long exposure, bone density, rather than producing the dust-induced lung fibrosis seen in pneumoconiosis.

Since pneumoconiosis is specifically a dust-particle disease of the lungs, and silica is the option that is deposited in and scars lung tissue through this mechanism, it is the correct cause.

Therefore, the correct answer is Silica.