Buildings and Streets that Clean the Air

An economically green material called photocatalytic concrete is sprouting up in cities across the world to help clean up air pollution.

The air-cleansing concrete acts as a catalyst to speed up the natural reactions that turn pollutants into harmless compounds. Similar to photosynthesis, photocatalytic concrete converts pollutants such as carbon and nitrogen oxides into safe compounds like carbon dioxide and nitrate when exposed to the sun’s UV rays. Not only does the concrete scrub out pollution, but it won’t deteriorate from the reactions and it even keeps grime from caking onto the buildings and streets.

The special ingredient that makes all this possible is titanium dioxide, which is already used in cosmetics, vitamins, and milk products. Scientists at Eindhoven University of Technology have found that this photocatalytic cement reduces nitrogen oxide pollution by an average of 19% per day and all the way up to an impressive 45% when the UV rays are strong and the humidity is low.

The Dives in Misericordia is among many other buildings that are already using this simple technology to clean up the smog and pollution that are weighing down on us. Next on the list will be the Gateway to the Midwest: The Missouri Department of Transportation is preparing to test and implement this new technology in St. Louis.

So why isn’t every smoggy city immediately jumping on board? The lack of awareness and the cost increase present roadblocks to this passive air-cleaning technology. The good news is that concrete constructions don’t need to be entirely photocatalytic: only a thin layer needs to be applied to the top of the structural concrete. This small additional step could substantially help to alleviate the ecological and health concerns of the looming pollution above us.

Photo courtesy of Taschen

Keara Wright

Aspiring creative author and astrophysicist, with degrees in Physics, Mathematics, and Psychology.

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