Which of the following pollutants is associated with brain damage?

Correct answer: Carbon(II) oxide (carbon monoxide).

Explanation: Carbon(II) oxide (CO) binds strongly to haemoglobin to form carboxyhaemoglobin, reducing oxygen delivery to tissues. The resulting hypoxia especially affects the brain, leading to neurological injury and possible long-term brain damage.

• Radioactive fallout — Causes radiation sickness and increases cancer risk; not specifically linked to typical “pollution” brain damage in this context.
• Biodegradable waste — Depletes dissolved oxygen in water bodies, harming aquatic life, not directly the human brain.
• Sulphur(IV) oxide (SO₂) — Mainly irritates the respiratory system and contributes to acid rain; not chiefly associated with brain damage.