Being Green; March 2009; Scientific American Earth 3.0; by Dawn Stover; 2 Page(s)
High on White Roofs
Painting your home or office building roof a light color or installing white shingles helps to reflect heat¿and reduces cooling costs. According to Hashem Akbari of Lawrence Berkeley National Laboratory, replacing a 1,000-square-foot dark roof with a white one can offset the emission of 11 tons of carbon dioxide annually. Roofs account for about 25 percent of the surface area in most cities. California has required heat-reflecting roofs on commercial buildings since 2005 and will require them for new and retrofitted residential buildings beginning in 2009. If white shingles aren¿t your style, manufacturers also offer heat-reflective coatings in darker colors for shingles, tiles and metal roofs.
Are Scooters Polluters?
Some people are turning to scooters to reduce their transportation costs. But even the cleanest gasoline-powered models typically emit more smog-forming
hydrocarbons and nitrogen oxides than a car because so little pollution-control equipment fits on them. On the positive side, scooters can help ease traffic congestion, minimize materials used in manufacturing and lessen carbon dioxide emissions (because they get better fuel economy). The greenest choice may be a ¿maxi scooter¿ that is as powerful and expensive as a motorcycle but runs on electricity, although that energy may be generated at a fossil-fuel-burning power plant. Here¿s a comparison.