Model Answer

Introduction

Particulate Matter (PM) pollution is a major contributor to poor air quality in urban centres like Delhi, with road dust and construction dust forming a significant share. To control this, chemical dust suppressants were tested by CPCB through a study conducted by EPRI and CSIR-NEERI in 2018.

Effectiveness of Chemical Dust Suppressants

1. Higher Efficiency than Water

   • Chemical suppressants were found to be 50–60% more effective than water sprinkling.
   • In Delhi trials, dust levels reduced by around 30% for nearly six hours, while water remains effective only for 10–15 minutes due to evaporation.

2. Surface Binding Action

   • These chemicals form a thin binding layer on surfaces.
   • This prevents dust particles from becoming airborne.

3. Useful at Construction and Traffic-heavy Sites

   • Particularly effective at construction zones, unpaved roads and industrial areas.
   • Suitable where dust generation is continuous.

Limitations of Chemical Dust Suppressants

1. Health and Environmental Risks

   • Chemical exposure can cause respiratory and skin irritation.
   • Chloride-based salts used in trials may damage soil quality, groundwater and vegetation with repeated use.

2. Limited Duration and Disturbance

   • Effectiveness reduces with vehicle movement, machinery operation and foot traffic.

Economic and Operational Constraints

1. High Costs and Frequent Application
   • Experts consider them uneconomical due to the need for reapplication every six hours.
   • Large-scale deployment requires substantial financial and logistical support.

Conclusion

Chemical dust suppressants offer a technically effective but environmentally and economically constrained solution to particulate pollution in Delhi. They are best used as a supporting tool within a broader, sustainable air pollution control strategy rather than as a standalone measure.