Context: A study commissioned by the Central Pollution Control Board (CPCB) has found that chemical dust suppressants are significantly more effective than water sprinkling in controlling particulate matter emissions from construction sites, roads, and industrial areas. The findings assume importance amid India’s worsening urban air pollution, particularly PM₁₀ and PM₂.₅ pollution.
What Are Chemical Dust Suppressants?
Chemical dust suppressants are specialised agents applied to exposed soil, roads, construction sites, and mining areas to reduce dust emissions.
They work by binding loose particles, increasing particle weight, or forming a surface layer that prevents dust from becoming airborne.
Common Types of Chemical Dust Suppressants
- Hygroscopic Salts
- Calcium chloride, magnesium chloride
- Absorb moisture from the air and keep surfaces damp for longer durations.
- Polymer-Based Suppressants
- Acrylic and vinyl-acetate polymers
- Form adhesive films that lock dust particles in place.
- Organic Binders
- Lignosulfonates (wood pulp derivatives)
- Bind soil particles naturally and are biodegradable.
- Surfactants
- Anionic surfactants
- Reduce water’s surface tension, allowing better spread and penetration.
- Bituminous or Petroleum Emulsions
- Harden into a crust that resists wind and vehicular disturbance.
Why Chemical Suppressants Are More Effective
1. Higher Dust Reduction
- Chemical suppressants reduce dust by 50–60%,
- Water sprinkling achieves only 25–30% reduction.
2. Longer Effectiveness
- Chemical treatment remains effective for several hours,
- Water dries up in 10–15 minutes, especially in hot or windy conditions.
3. Better Control of Fine Particles
- More effective against PM₁₀ and PM₂.₅, which are most harmful to health.
4. Cost Efficiency
- Six-hour chemical treatment costs around ₹100,
- Water sprinkling for the same duration costs nearly ₹2,160, considering repeated application.
Limitations and Concerns
- Traffic Sensitivity: Heavy vehicular movement reduces durability.
- Health Risks: Improper use may cause mild skin or respiratory irritation.
- Environmental Impact: Repeated application can affect soil health, groundwater, and nearby vegetation.
- Weather Dependence: Extreme rainfall or humidity can reduce effectiveness.
Policy Significance
- Supports CPCB and State Pollution Control Boards in shifting from inefficient water sprinkling to evidence-based dust control methods.
- Can improve compliance under Construction and Demolition Waste Management Rules, 2016 and NCAP goals.
- Highlights the need for guidelines, monitoring, and environmental safeguards before large-scale adoption.
Conclusion
The CPCB study establishes chemical dust suppressants as a cost-effective and longer-lasting solution to urban dust pollution. However, their use must be regulated, location-specific, and environmentally monitored to ensure sustainable pollution control without unintended ecological harm.