America's Dirtiest Vehicles

America's Dirtiest Vehicles - The dirtiest new vehicles in America. These rides are the worst offenders when it comes to air pollution and carbon footprint. Nobody wants to be known as the dirtiest, at least not when it comes to air pollution. The good news is that since 1975, overall new passenger car emissions of greenhouse gasses have decreased, and fuel efficiency has increased. The trends seem likely to continue, based partly on technological innovation, partly on more stringent government regulation, and partly on consumer interest and demand.