Up on the Housetop, Granules Cool

Created as a temporary clean air measure, 3M's roofing granules are designed to capture air pollution while using sunlight to transform the smoggy chemicals into water-soluble ions that later wash away.

About a decade ago, 3M created "cool roofing" granules to help new residential projects comply with standards mandating additional rooftop insulation for cooling. When tested, the granules were found to remove roughly the same amount of air pollution as the nearby trees when spread over an average-sized roof, Fast Company reports. The water runoff created by the granules was found to have minimal impact, according to the company's chief sustainability officer Gayle Schueller. “When we innovate, we start with an understanding of where there is a problem, and we identified the issue of smog in cities,” Schueller says.

For the past several weeks, the air quality in California has made headlines. Raging wildfires in the northern and southern parts of the state created clouds of ash and dangerously high toxicity levels in the atmosphere. The fires created a state of emergency, but in many parts of the country, that poor air quality is a daily issue, not one created by natural disasters. Over the summer, southern California violated federal smog standards for 87 days in a row. Around 41 percent of people in the U.S. live with regular exposure to poor air quality.

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