Subject: Environment & Ecology

Answer:

Photochemical smog, a contemporary environmental challenge, represents a complex mixture of air pollutants formed through photochemical reactions. The 1999 Gothenburg Protocol marks a significant international effort to combat transboundary air pollution, making the understanding of smog formation and mitigation crucial for environmental management.

Formation of Photochemical Smog

• Primary Pollutants: Formation begins with the emission of nitrogen oxides (NOx) and volatile organic compounds (VOCs) from vehicular exhausts and industrial emissions.

• Photochemical Reactions:

  • In presence of sunlight, NOx undergoes photolysis to form ground-level ozone (O3).
  • Secondary pollutants like peroxyacetyl nitrate (PAN) and aldehydes are formed through complex chemical reactions.
  • Temperature inversions trap these pollutants near the ground level, intensifying the smog.

Effects of Photochemical Smog

• Health Impacts:

  • Causes respiratory ailments, eye irritation, and cardiovascular problems.
  • According to recent data, Delhi's AQI reached 171, posing severe health risks.
  • Particularly harmful to vulnerable populations like children and elderly.

• Environmental Impacts:

  • Damages vegetation through oxidative stress.
  • Reduces visibility affecting transportation.
  • Contributes to acid rain formation.

Mitigation Strategies

• Technological Solutions:

  • Implementation of anti-smog guns and water sprinklers.
  • Use of AI-based monitoring systems for real-time pollution tracking.
  • Installation of air purifiers in urban hotspots.

• Policy Measures:

  • National Clean Air Programme (NCAP) targeting 40% reduction in PM concentrations by 2026.
  • Construction bans during severe pollution episodes.
  • Promotion of public transportation and electric vehicles.

The Gothenburg Protocol

• Key Features:

  • Sets emission ceilings for sulfur dioxide, nitrogen oxides, VOCs, and ammonia.
  • Promotes best available techniques for pollution control.
  • Emphasizes international cooperation in air quality management.

• Implementation Mechanism:

  • Regular monitoring and reporting requirements.
  • Technical and financial assistance for developing nations.
  • Periodic review and updates of emission targets.

The fight against photochemical smog requires a multi-pronged approach combining technological innovation, policy implementation, and international cooperation. Success stories like the Stockholm Convention and Montreal Protocol demonstrate that with concerted global efforts, air quality challenges can be effectively addressed.