A team of University of California, Riverside’s Bourns College of Engineering students has developed a titanium dioxide roof tile coating that removes up to 97 percent of smog-causing nitrogen oxides.
The students' calculations show that 21 tons of nitrogen oxides would be eliminated daily if tiles on one million roofs were coated with their titanium dioxide mixture.
The researchers coated two identical, off-the-shelf clay tiles with different amounts of titanium dioxide, a common compound found in everything from paint to food to cosmetics. The tiles were then placed inside a miniature atmospheric chamber that the students built out of wood, Teflon, and PVC piping.
The chamber was connected to a source of nitrogen oxides and a device that reads concentrations of nitrogen oxides. The students used ultraviolet light to simulate sunlight, which activates the titanium dioxide and allows it to break down the nitrogen oxides. They found the titanium dioxide coated tiles removed between 88 percent and 97 percent of the nitrogen oxides.
Also: Learn about Spectroscopic Determination of Trace Contaminants in High-Purity Oxygen.