The Stony Brook University researchers revealed that sulfur dioxide, a major contributor to air pollution, is removed from the air by concrete surfaces.

Researchers Alex Orlov and colleagues discovered how concrete interacts and eliminates sulfur and nitrogen oxides. Their findings could be a significant step toward the practice of using waste concrete to minimise air pollution.

According to the World Health Organisation, as many as seven million premature deaths of people worldwide may be linked to poor air quality and pollution. Sulfur dioxide emissions are among the most common pollutants into the air globally, with power plants emitting the most sulfur dioxide. Cement kilns also produce approximately 20 percent of all sulfur dioxide industrial emissions.

“Even though producing concrete causes air pollution, concrete buildings in urban areas can serve as a kind of sponge adsorbing sulfur dioxide to a high level,” explained Orlov. “Our findings open up the possibility that waste concrete coming from building demolitions can be used to absorb these pollutants.”

He added that concrete remains the most widely used material in the world and is inexpensive. Because of this, Orlov emphasized that “the strategy of using pollution causing material and turning it into an environmental solution could lead to new thinking in urban design and waste management.”

Orlov cautioned that the capacity for concrete to absorb pollutants diminishes over time as the material ages. Crushing concrete, however, can expose new surfaces and restore its pollution removing properties.

The researchers used various cement and cement-based building materials to conduct their experiments.

The results are published in the Journal of Chemical Engineering.