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"By installing roofing tile that contains titanium dioxide, homeowners can scrub the air of an average of 10,800 miles of smog per year."^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.mnn.com/your-home/remodeling-design/stories/new-roofing-tiles-may-make-pollution-a-thing-of-the-past>