If the roads are going to allow you to drive an air-polluting automobile, they could at least do their part to take those toxins out of the sky. Dutch scientists from University of Twente have created concrete paving stones with an additive created from titanium dioxide. The nitrogen oxides released by cars bind to the additive, changing from a greenhouse gas into benign nitrates. Officials in Overijssel, a province in the eastern part of the Netherlands, plan to try out the new green bricks. They're building a new road in a town called Hengelowith half air-purifying bricks and half regular concrete. Once it's completed and people begin driving on the road, scientists will measure which area boasts cleaner air. The results should come next summer. In the meantime, keep riding those bicycles, Holland.