Smog-Eating Photocatalytic Coating

Recently, the Delhi government in collaboration with the Indian Institute of Technology Madras has initiated studies on “smog-eating” photocatalytic coatings for roads. The aim is to explore innovative solutions to tackle worsening air pollution, particularly in urban environments like Delhi.

About Smog-Eating Photocatalytic Coating

Smog-eating photocatalytic coating is a special surface treatment applied to roads and buildings that helps in reducing air pollution by breaking down harmful pollutants.

It is mainly designed to neutralise gases such as nitrogen dioxide and volatile organic compounds, which are major contributors to toxic urban smog.

A key material used in this coating is titanium dioxide, which is widely preferred because it is low-cost, chemically stable, and compatible with conventional construction materials.

The coating uses titanium dioxide-based photocatalysis to actively reduce air pollutants in the environment.

Working Mechanism

The working principle of this coating is based on photocatalysis, where light energy triggers a chemical reaction on the coated surface.

When sunlight falls on titanium dioxide, it activates a reaction that breaks down harmful pollutants into less harmful or harmless substances. This process helps in reducing both air and surface pollution over time.

The coating works by using solar energy to convert toxic pollutants into non-toxic compounds.

Concept of Smog

Smog refers to a type of air pollution formed by the combination of smoke and fog, resulting in reduced visibility and harmful air quality. It is not a single pollutant but a mixture of several atmospheric contaminants formed under specific environmental conditions.

Smog is broadly classified into two types:

1. Sulfurous Smog

This type is caused by high concentrations of sulphur oxides in the atmosphere. It is mainly associated with the burning of sulphur-rich fossil fuels like coal and is more common in industrial regions.

2. Photochemical Smog

This type occurs in urban areas with high vehicular emissions. It is formed when sunlight reacts with pollutants such as nitrogen oxides and hydrocarbons, leading to the formation of harmful secondary pollutants like ozone.

Photochemical smog is a major urban problem linked to vehicle emissions and sunlight-driven chemical reactions.

Significance of the Technology

The development of smog-eating coatings offers a promising approach to urban air quality management. Instead of only controlling emissions at the source, this technology helps in actively cleaning the air at the surface level.

If scaled effectively, it can complement existing pollution control measures such as emission norms and public transport improvements.

This technology provides a proactive and surface-level method of reducing urban air pollution.

Conclusion

The smog-eating photocatalytic coating initiative led by the Delhi government and Indian Institute of Technology Madras reflects an innovative approach to addressing air pollution. By using light-activated materials like titanium dioxide, it offers a scientific method to reduce harmful gases in urban environments.