Researchers from the Eindhoven University of Technology in the Netherlands claim to have invented a new type of paving material that actually removes some pollutants from the air as vehicles travel over the surface.
Combined with concrete or normal asphalt, the new material is able to eliminate 25% to 45% of nitrogen oxides from vehicle gases.
According to the scientists, the paving material is impregnated with titanium dioxide that works in combination with sunlight to cause a chemical reaction that eliminates the nitrogen oxide from the air and converts it into nitrate. They also said that the nitrate is then rinsed away by rain.
Last year, the research team was only able to conduct its first area-wide tests of the material. Then, they covered about 1,000 square meters of existing road surface with the air-purifying concrete paving stones and 1,000 square meters was surfaced with normal paving stones for comparison. The best part of the material is that it doesn’t even cost so much more than a normal roadway to construct.
After that, they performed measurements at various levels, between 0.5 and 1.5 meters, above the road surface on both types of paving stones and found that unlike normal paving stones, the air above the air-purifying pavement has half the nitrogen oxides. Another advantage of this material is that it can break down dirt and algae, keeping the stones very clean.
Besides the advantages it has, there are some disadvantages. It has been found that an excess of nitrates in drinking water can cause health issues (this happens when the nitrates reach groundwater). Another problem is that the material costs 10% more to install, compared to traditional road materials (but since it eliminates nitrogen oxide from the air, I think it’s worth the money).