Can 'Smog-Eating' Road Coatings Clean Delhi's Toxic Air?

Scientists at the Indian Institute of Technology (IIT) Madras are investigating the potential of "smog-eating" photocatalytic coatings to purify Delhi's air. This initiative is part of a six-month collaboration with the Delhi government, aiming to determine if these coatings on public spaces can effectively reduce nitrogen dioxide (NO₂) and volatile organic compounds (VOCs).

The research, led by Professor Somnath C Roy, will commence with laboratory testing designed to simulate Delhi's real-world pollution conditions. Researchers plan to recreate smog using actual data on pollution levels and traffic patterns to assess how the "smog-eating" surfaces perform.

The core of the study focuses on titanium dioxide (TiO₂), a material that reacts under sunlight. When exposed to UV light, TiO₂ generates electrons that break down pollutants like NO₂ into simpler substances such as nitrogen and oxygen.

IIT Madras will explore various deployment methods, including mixing TiO₂ into concrete and asphalt, applying it as coatings, or developing panels similar to solar panels. These "smog-eating" panels could directly interact with ambient air, potentially impacting pollution levels in high-emission areas.

However, the technology is not a standalone solution but a continuous background process intended to work alongside existing pollution-control measures. Challenges such as dust settling on surfaces and reduced sunlight intensity during peak smog periods will also be investigated, with periodic cleaning and testing under varied lighting conditions being crucial.

TiO₂ is described as a stable, commercially available, and relatively inexpensive material that does not significantly increase construction costs. The project's initial phase will focus on optimizing the concentration of TiO₂ before final cost calculations can be made.