Cities get some face lifts during summer months, when traffic is lower and most of its dwellers escape for vacations. Such is the case of Spain's capital city Madrid, which is renewing some of the asphalt on its streets with a bituminous mix called noxer that includes titanium oxide. This substance is claimed to capture the nitrogen oxides (NOx) at
pumps and catalyzes and stores the resulting less-polluting oxides until they're washed away by rainwater. It uses solar radiation to work and Madrid city council claims that it can capture up to 90 percent of these oxides on a sunny day. Additionally, the city is installing asphalt which used recycled tires on one of the city's main entries to reduce noise pollution.