Aerosol
Aerosols are tiny solid or liquid particles suspended in a gas, like air, and can be natural (e.g., volcanic ash, sea spray) or human-caused (e.g., pollution, smoke). They play a role in climate, air quality, and can also be a source of health problems.
What are Aerosols?
- Definition:An aerosol is a suspension of fine solid particles or liquid droplets in a gas, most commonly air.
- Sources:
- Natural: Sea spray, mineral dust, volcanic eruptions, and natural fires.
- Human-caused: Industrial emissions, burning fossil fuels, and agricultural activities.
- Composition:Aerosols can be composed of various substances, including:
- Inorganic: Sea salt, dust, and sulfates from volcanic eruptions.
- Organic: Soot, organic carbon, and black carbon from burning fuels.
Key Takeaways
- Aerosols and greenhouse gases (GHGs) interact differently:
- GHGs (e.g., CO₂, CH₄) trap heat, causing long-term warming.
- Aerosols (e.g., sulphates, nitrates) scatter sunlight, creating a temporary cooling effect.
- Removing aerosols too quickly could accelerate warming in highly polluted regions like India.
- India’s Dual Challenge:
- Balancing air pollution control with climate mitigation.
- Cutting aerosols without reducing GHGs may expose vulnerable populations to extreme heat.
Scientific Findings
- Aerosols have masked global warming effects:
- India’s warming trend since 1901 (~0.7°C increase) was partially offset by aerosols and land-use changes.
- Without aerosols, India’s temperature would have risen by ~2°C instead of 0.54°C (1906-2005).
- Aerosols also affect rainfall:
- Aerosols contribute to weaker Indian monsoon rainfall by causing uneven cooling, particularly in the northern hemisphere.
- Some studies indicate that reducing aerosols could improve monsoon precipitation, but regional effects remain uncertain.
Policy Implications
- Achieving Net-Zero Carbon Alone Is Not Enough:
- Sudden aerosol reductions could lead to short-term climate shocks, including extreme heat.
- Policymakers must focus on heat adaptation strategies in highly polluted areas (e.g., Indo-Gangetic plains).
- Balancing Climate and Health Benefits:
- Immediate air quality improvements will reduce respiratory diseases and improve public health.
- Cities must strengthen heat action plans to prepare for potential warming effects.
- Trade-offs should be considered when designing industrial and environmental policies.
