Model Answer
0 min readIntroduction
Air pollution is a major global environmental health crisis, contributing to millions of premature deaths annually. The World Health Organization (WHO) periodically updates its Global Air Quality Guidelines (AQGs) based on emerging scientific evidence. Recently, in September 2021, the WHO released its revised AQGs, significantly lowering the recommended levels for several key pollutants. These revisions reflect a growing understanding of the adverse health effects of air pollution, even at low concentrations, and necessitate a re-evaluation of national air quality management strategies, particularly in highly polluted countries like India, where the National Clean Air Programme (NCAP) is the primary policy intervention.
Revised WHO Global Air Quality Guidelines (AQGs) – Key Points
The revised AQGs set stricter limits for air pollutants, aiming to protect public health. Key changes include:
- PM2.5: Reduced from 10 µg/m³ (annual mean) to 5 µg/m³. No lower limit was previously recommended.
- PM10: Reduced from 20 µg/m³ (annual mean) to 10 µg/m³.
- Ozone (O3): 8-hour mean reduced from 100 µg/m³ to 60 µg/m³.
- Nitrogen Dioxide (NO2): Annual mean reduced from 40 µg/m³ to 10 µg/m³.
- Sulfur Dioxide (SO2): Daily mean reduced from 20 µg/m³ to 5 µg/m³.
- Carbon Monoxide (CO): 8-hour mean reduced from 10 mg/m³ to 4 mg/m³.
The WHO emphasizes that these guidelines are not legal targets but provide a scientific basis for policy-making to protect public health. The revised guidelines acknowledge that there is no safe level of some pollutants, particularly PM2.5.
Comparison with 2005 Guidelines
The 2021 AQGs represent a substantial tightening of standards compared to the 2005 guidelines. The most significant changes are the drastically reduced limits for PM2.5 and NO2. The 2005 guidelines were based on the available evidence at the time, but subsequent research has demonstrated the harmful effects of air pollution at much lower concentrations than previously thought. The following table summarizes the key differences:
| Pollutant | 2005 WHO AQG (Annual Mean) | 2021 WHO AQG (Annual Mean) |
|---|---|---|
| PM2.5 | 10 µg/m³ | 5 µg/m³ |
| PM10 | 20 µg/m³ | 10 µg/m³ |
| NO2 | 40 µg/m³ | 10 µg/m³ |
| SO2 | 20 µg/m³ (24-hour mean) | 5 µg/m³ (24-hour mean) |
Implications for India’s National Clean Air Programme (NCAP)
India’s NCAP, launched in 2019, aims to reduce PM2.5 and PM10 concentrations by 20-30% by 2024, compared to 2017 levels. However, the current NCAP targets are significantly less stringent than the revised WHO AQGs. To align with the new guidelines, the following changes are required:
- Stricter Emission Standards: Implement more stringent emission standards for vehicles, industries, and power plants. This includes accelerating the adoption of BS-VI norms nationwide and promoting cleaner fuels.
- Expanded Monitoring Network: Increase the number of air quality monitoring stations, particularly in rural areas, to provide a more comprehensive picture of air pollution levels.
- Source Apportionment Studies: Conduct detailed source apportionment studies in each city to identify the major contributors to air pollution and tailor interventions accordingly.
- Strengthened Enforcement: Enhance enforcement of air quality regulations and impose stricter penalties for violations.
- Inter-sectoral Coordination: Improve coordination between different government departments, including environment, transport, and industry, to address air pollution effectively.
- Public Awareness: Raise public awareness about the health risks of air pollution and promote behavioral changes to reduce exposure.
- Financial Resources: Significantly increase financial resources allocated to air quality management, including funding for research, technology development, and implementation of control measures.
Currently, only a handful of Indian cities meet the revised WHO AQG standards. Achieving these standards will require a paradigm shift in India’s approach to air quality management, moving beyond incremental improvements to a more ambitious and transformative strategy.
Conclusion
The revised WHO AQGs represent a crucial step towards protecting global public health from the devastating effects of air pollution. For India, achieving these standards presents a significant challenge, requiring substantial investments, policy reforms, and inter-sectoral coordination. While the NCAP is a positive step, it needs to be significantly strengthened and aligned with the WHO guidelines to ensure cleaner air for all citizens. A proactive and ambitious approach is essential to mitigate the health and economic costs of air pollution and create a sustainable future.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.