PM2.5 POLLUTION SOURCES IN NORTHERN INDIA

GS3 ENVIRONMENT: 

1. Overview

Northern India, especially the Indo-Gangetic Plain, faces severe air quality issues. A study in Nature Communications analyzes PM2.5 sources and their health impacts, stressing the need for localized mitigation efforts.

2. PM2.5 Composition

• Samples from five urban and rural locations were analyzed.
• Delhi: Dominated by vehicular emissions and residential heating.
• Outside Delhi: Higher levels of ammonium sulfate and biomass-burning aerosols.

3. Health Risks

• PM2.5’s oxidative potential (harm-causing ability) is influenced by organic aerosols.
• These aerosols stem from incomplete combustion of biomass and fossil fuels.
• Traffic and residential emissions are major contributors to health risks.

4. Seasonal Variations

• Hydrocarbon-like organic aerosols remain high throughout the year.
• Winter months witness a surge in primary organic aerosols due to cow dung burning for heating and cooking.
• Cold-season concentrations can be 10 times higher than in warmer months.

5. Role of Traffic Emissions

• Vehicles significantly contribute to PM2.5 pollution.
• Hydrocarbon-like organic aerosols from traffic make up 40% of urban PM2.5 in warmer months.

6. Global Comparison

• Indian cities exhibit PM2.5 oxidative potential up to five times higher than cities in China and Europe.
• This highlights the urgency of tackling air pollution in India.