Ammonium Sulphate and PM2.5: CREA Finds a Third of Pollution
Why in the news
A study by the Centre for Research on Energy and Clean Air (CREA) showed secondary pollution, led by ammonium sulphate, drives a large part of India’s fine particle pollution.
Key facts
| Measure | Value |
|---|---|
| Average concentration | 11.9 µg/m³ |
| Share of PM2.5 mass | 34% |
| Thermal plants’ share of SO2 | Over 60% |
| Plants with FGD | 8% |
- Formation: sulphur dioxide reacts with ammonia (NH3) in the air.
- Secondary pollutants: primary emissions from vehicles, coal plants and biomass burning react with water vapour and ammonia; often more harmful.
- Government was reportedly weighing dropping the FGD requirement.
CREA recommendations
- Timely, mandatory FGD in coal plants.
- Efficient fertiliser use to cut ammonia.
- Strict enforcement of emission norms, with source-specific action.
Exam angle
- Precursor gases: SO2 and NH3. Think tank: CREA.