Toxicity-Based Air Pollution Thresholds Explained for India

Toxicity-Based Air Pollution Thresholds Explained for India

Why in the News?

A recent study in Kolkata has revealed that PM2.5 toxicity rises sharply after crossing a concentration threshold of 70 µg/m³, urging policymakers to factor in toxicity, not just concentration, in framing air quality standards for better health protection. This research sheds light on the PM25 toxicity threshold that could influence future policy decisions.

Study Findings on PM2.5 Toxicity:

• Researchers from Bose Institute, Kolkata conducted a long-term (2016–2023) study on PM2.5 toxicity.
• Found that toxicity spikes after 70 µg/m³, peaking around 130 µg/m³, beyond which it stabilizes.
• Below 70 µg/m³, air pollution is still harmful, but the body can cope better.
• The body’s defense mechanisms, including antioxidants, fail at higher pollution levels, leading to oxidative stress.
• ROS (Reactive Oxygen Species), meant to fight pollutants, ends up damaging healthy cells when in excess.

Reasons Behind Sudden Spike in Toxicity

• Biomass burning and solid waste are major contributors to rising toxicity.
• Vehicular emissions also contribute but to a lesser extent.
• The composition of PM2.5 varies by city, making the toxicity threshold city-specific.
• The study underscores that toxicity depends on chemical makeup, not just quantity.

Policy Implications and Way Forward

• Current standards are based solely on concentration, e.g., 40 µg/m³ (annual safe limit).
• The study calls for toxicity-based thresholds to trigger warnings/emergency actions.
• Suggests a need for localized air quality indices considering oxidative stress potential.
• May guide more targeted, health-focused regulations in Indian cities, potentially influencing policies like the foreign trade policy 2021-26 highlights to address environmental concerns.
• This research could lead to the recognition of May 7 special day in India as National Clean Air Awareness Day, emphasizing the importance of understanding and mitigating air pollution toxicity.