When it comes to air pollution, most attempts to reduce it look at the source rather than after-treatment. Making new cars cleaner and more efficient is only part of the solution; finding ways to treat the pollution coming out of older cars is just as important and there are already millions of heavy-polluting vehicles out on the roads, many of which will be spitting out smog for years to come.
Fortunately, there are scientists out there developing technologies to help reduce the harmful effects of all those heavy-polluting vehicles already out on the roads. Scientists at the Eindhoven University of Technology (TU/e) in the Netherlands, for example, are trialing a special concrete that actually purifies the air, stripping it of harmful elements such as nitrogen oxides (NOx) commonly found in tailpipe emissions and harmful to the human body’s respiratory system.
The special concrete has a top layer impregnated with titanium dioxide, a chemical that when exposed to sunlight binds with oxides of nitrogen produced by cars and other pollution sources. The pollutants are transmuted into nitrates, which are not harmful to the environment, during the process. Then the next time the rain comes along, it washes the stones clean.
Initial testing of a patch of roadway in the Dutch town of Hengelo has shown a reduction of nitrogen oxide concentration of about 25 to 45 percent. In addition to the air purifying benefits, the concrete also breaks down algae and dirt, so that they always stay clean.
The best part is that the material, manufactured by Struyk Verwo Infra, only increases road costs by about 10 percent and is fully applicable for asphalt surfaces as well.