Photocatalytic concrete is a new hybrid material that is being used to significantly reduce air pollution and is able to maintain a clean surface. The Portland cement mixture incorporates titanium dioxide that, when activated by UV rays, acts as a catalyst, “accelerat[ing] the oxidation process that converts nitrogen oxides and other smog components such as fine particulate material, carbon monoxide and sulphur dioxide, to less harmful compounds.” [i]
Varying projects have tested and used this material for its self-cleaning properties and more importantly, to help reduce emissions. These results note that photocatalytic concrete, when applied within an area of a soccer field, can remove emissions that equal approximately 190,000 car-km per year and merely 1 sq meter of this material removes up to 60 mg of NOx per day.[ii] The material works best when in close proximity to the source of pollution; therefore using the material in urban locations is ideal. Photocatalytic concrete is being tested and used for roads, tunnels, sound walls, and buildings. The varying uses have resulted in statistics noting 20-70% pollutant reduction within the materials vicinity.
One project that is noted as being the “Greenest Street in America” is Cermak Road in Chicago. The project utilized photocatalytic concrete for nearly all of its paving surfaces. Historically, Chicago and heavy storms have not mended well.
Sewer overflows have forced stormwater to migrate to the Chicago River, Lake Michigan, eventually moving down the Mississippi toward the Gulf of Mexico. Therefore, the integration of the photocatalytic concrete on the roadways and the permeable pavement along with the addition of landscape design in the form of rain gardens and bio-swales have helped to mitigate hazardous overflows and pollution levels while also maintaining a clean surface.
Photocatalytic concrete is one of many new and emerging sustainable technologies that is helping to reduce pollution’s impact on our environment and our health. While it is helping us to mitigate the effects of pollution, it is also a temporary fix. I cant help but to think that–as great as this material is–we are covering up our tracks with temporary bandaids. Instead of making materials that can eat the smog we emit, we need to focus on the source of the problem. Why manufacture and use technologies that pollute in the first place?