Photocatalytic Coating Trials Target Delhi Air Pollution

The Delhi government, in collaboration with the Indian Institute of Technology (IIT) Madras, has initiated studies on “smog-eating” photocatalytic coatings on roads. The initiative aims to explore innovative, science-based solutions to combat rising air pollution levels in urban areas, particularly harmful gaseous pollutants.

What is Photocatalytic Coating?

Photocatalytic coating is an advanced material designed to neutralise harmful air pollutants such as nitrogen dioxide and volatile hydrocarbons. It typically uses titanium dioxide (TiO₂), a low-cost and chemically stable compound that can be easily applied to construction surfaces like roads and buildings. Its compatibility with conventional materials makes it suitable for large-scale urban deployment.

Working Mechanism of the Technology

The coating works through a process called photocatalysis. When exposed to sunlight, titanium dioxide becomes activated and triggers chemical reactions that break down harmful pollutants into less toxic or harmless substances. This process helps in reducing air pollution and contributes to environmental cleaning by purifying both air and surfaces.

Potential Benefits and Applications

TiO₂-based photocatalytic materials have demonstrated potential in gaseous depollution. When applied on roads or infrastructure, they can continuously interact with pollutants, offering a passive method of air purification. Such coatings may complement existing pollution control measures, especially in densely populated and traffic-heavy urban regions.

Important Facts for Exams

• Titanium dioxide (TiO₂) is widely used in photocatalytic coatings.
• Photocatalysis uses light energy to break down pollutants.
• These coatings help reduce nitrogen oxides and hydrocarbons.
• They can be applied on roads and building surfaces for air purification.

Understanding Smog and Its Types

Smog refers to a form of air pollution resulting from the combination of smoke, pollutants and fog. It includes a wide range of atmospheric pollutants formed under specific environmental conditions. Two main types are recognised: sulfurous smog, caused by high concentrations of sulfur oxides from coal-based fuels, and photochemical smog, common in urban areas due to emissions from automobiles and sunlight-driven chemical reactions.