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UPSC Prelims 2019 · Environment · Pollution Files
Consider the following statements: Which of the statements given above is/are correct?
- Agricultural soils release nitrogen oxides into environment.
- Cattle release ammonia into environment.
- Poultry industry releases reactive nitrogen compounds into environment.
- (a) 1 and 3 only
- (b) 2 and 3 only
- (c) 2 only
- (d) 1, 2 and 3
Show the answer and explanation
Answer: (d) 1, 2 and 3
All three release reactive nitrogen.
Statement by statement
1. ✓ CORRECT Fertilised soils release NOₓ and N₂O.
2. ✓ CORRECT Cattle dung and urine release ammonia.
3. ✓ CORRECT Poultry litter releases ammonia and other reactive nitrogen.
The idea
Air is 78% nitrogen, but that nitrogen (N₂) is inert and harmless. Reactive nitrogen means the active forms: ammonia, nitrate, nitrogen oxides, nitrous oxide. Farming adds huge amounts of these through fertiliser and animal waste, and most of it leaks into air and water.
Urea is applied to a field → The crop uses only about a third → Some escapes as ammonia gas → Some washes down as nitrate into groundwater → Some leaves as nitrous oxide
Also know
Damage done: nitrate in drinking water (blue baby syndrome), algal blooms in lakes and seas, ammonia forming fine particles in the air, and nitrous oxide, which is both a strong greenhouse gas and an ozone-depleting gas. Animal urine and poultry droppings are rich in nitrogen and release ammonia as they break down. Neem-coated urea slows the loss.
🔒 Indian Nitrogen Assessment (2017): agriculture = biggest source of reactive nitrogen.