Gasoline engines now in production can be nearly pollution-free, a California university engineering laboratory reports after three years of study, according to USA Today. The finding suggests Americans can enjoy much cleaner air without the high price of electric cars. "You won't get to zero (emissions), but you will get pretty close," says Joseph Norbeck, director of the facility that performed the challenging tests at the University of California-Riverside. For now, the promising technology is limited to California because to work right, the engines require low-sulfur gasoline that is widely available only there. It probably will take a federal mandate for the clean fuel to become available across the United States, opening the door to cleaner-burning engines everywhere, according to USA Today.