Key Findings on Air Pollution in Delhi
The Commission for Air Quality Management (CAQM) conducted a synthesis of studies on air pollution in Delhi, identifying the primary sources of winter pollution.
Main Contributors to Air Pollution
- Secondary Particulate Matter: The largest contributor at 27%.
- Transport: Responsible for 23% of pollution.
- Biomass Burning: Accounts for 20%, including municipal waste and crop residue burning.
- Dust: Contributes 15%.
- Industry: Adds 9% to air pollution.
Study and Report Details
- The CAQM's report was produced following a Supreme Court directive to identify major causes of worsening AQI.
- Existing studies were compiled, but they used differing approaches to analyze pollution sources.
- A new emissions inventory and source apportionment study will be created by institutions including IIT Delhi and the Automotive Research Association of India.
Future Research and Tools
- Studies will use 2026 as the base year for an updated emissions inventory.
- The Air Quality Early Warning System and Decision Support System, developed by IITM Pune, will benefit from these studies.
- The Decision Support System was previously suspended due to forecasting inaccuracies.
Role of Ammonia and Other Compounds
Source apportionment studies indicate the role of ammonia in forming secondary particulates. Ammonia primarily comes from fertilizers and livestock excreta.
- India's total ammonia emissions were 10.54 Tg in 2022, with synthetic fertilizers and livestock excreta as dominant sources.
- SO2 and NOx emissions, mainly from coal and brick kilns, combine with ammonia to form harmful aerosols.
Health Implications
- Between 25% to 60% of PM2.5 is composed of sulphates and nitrates, posing significant health risks.
- Fine particles can exacerbate conditions like asthma, lung cancer, and chronic obstructive pulmonary disease.
