Without knowing it, most Americans rely every day on a class of chemicals called per- and polyfluoroalkyl substances, or PFASs. These man-made materials have unique qualities that make them extremely useful. They repel both water and grease, so they are found in food packaging, waterproof fabric, carpets and wall paint.
Residential solar power is on a sharp rise in the United States as photovoltaic systems become cheaper and more powerful for homeowners. A 2012 study by the U.S. Department of Energy (DOE) predicts that solar could reach 1 million to 3.8 million homes by 2020, a big leap from just 30,000 homes in 2006.