Mention two harmful effects of noise pollution.

1. Prolonged exposure to loud noise damages the sensory hair cells of the organ of Corti, causing partial or permanent DEAFNESS.
2. It causes physical and mental stress — HYPERTENSION, a raised heart rate, headache, sleeplessness, irritability and difficulty in concentrating.

Two effects, one mark each, and they should differ in kind: one on hearing, one on general health.

THE SAFE LIMIT is about 80 decibels for continuous exposure. Above that the damage accumulates over years, which is why industrial deafness develops gradually rather than suddenly.

The hearing loss is SENSORINEURAL — the hair cells of the organ of Corti do not regenerate, so unlike a damaged eardrum the damage is PERMANENT. That point is worth making, and it is exactly what the 2026 paper examines through the quarry worker.

Sources: traffic, loudspeakers, industrial machinery, aircraft, firecrackers.