The National Green Tribunal (NGT) has sought a response from the Central government on the implementation of Central Pollution Control Board (CPCB) recommendations to control ozone levels in Delhi.
Key findings of the CPCB report
- Ozone levels above standards: Ozone levels were found to be above the national standard (100 µg/m³, 8 hours) at several monitoring stations.
Highest levels
- Nehru Nagar: 9 µg/m³ (56 days)
- Patparganj: 3 µg/m³ (45 days)
- RK Puram: 4 µg/m³ (hazardous levels in April-May 2023)
- Aurobindo Marg: Elevated levels recorded for 38 days.
- Traffic-affected areas: Hazardous ozone levels were observed in heavy traffic areas during April-May 2023.
Major causes
- Emissions from vehicles, biomass burning, industrial activities.
- Transboundary emissions and biological sources also contribute.
Ground-level ozone pollution
- Ground-level ozone (O₃) is ozone formed near the Earth’s surface, by chemical reactions in the atmosphere.
- It is different from the protective ozone layer present in the stratosphere and acts as a harmful pollutant.
- Effects on health and environment: Ground-level ozone causes serious health hazards and environmental damage.
Process of formation
- Type: It is a secondary pollutant (not emitted directly).
- Chemical reaction: It is formed by reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs).
Sources
- NOx: Vehicles, power plants, industrial processes.
- VOCs: Vehicles, petrol pumps, solvents, garbage burning.
- Condition: This reaction takes place in the presence of sunlight, so ozone formation is more on sunny and warm days.
Effects of Ground Level Ozone Pollution
Health Effects
- Respiratory Problems: Ground level ozone causes respiratory problems and aggravates conditions such as asthma and heart disease.
- Long-term effects: Continuous exposure to ozone can reduce lung capacity and cause permanent damage.
- Expected consequences by 2050: If emissions are not controlled, India could have more than one million deaths due to ozone exposure by 2050.
Environmental Effects
- Impact on Agriculture: Ozone damages crops, leading to reduced agricultural production.
- Impact on Forests: Ozone affects tree growth and photosynthesis, thereby affecting plant life.
Suggestions for Ozone Control
- Control of major components: Ozone control can be achieved primarily by reducing catalysts, such as nitrous oxide (NOx), volatile organic compounds (VOCs), methane, and carbon monoxide (CO).
- Limitations of local control: Local control of catalysts may not significantly reduce ozone levels, as both ozone and catalysts can travel long distances.
- National level initiatives: National level initiatives and policies are needed to effectively control these catalysts.