The Red Hook, Brooklyn-based mobile retail bakery runs on compressed natural gas (CNG), which produces less exhaust and carbon emissions than diesel and gasoline do. While actual emissions will vary with engine design, the U.S. Environmental Protection Agency estimates that compared with gasoline, CNG offers potential reductions in carbon-monoxide emissions of 90 to 97 percent, as well as reductions in carbon-dioxide emissions by 25 percent. Based on natural gas's "inherently 'cleaner' chemical properties," the EPA says, we can also expect potential reductions in nitrogen-oxide emissions of 35 to 60 percent, potential reductions in nonmethane hydrocarbon emissions of 50 to 75 percent, fewer toxic and carcinogenic pollutants, as well as the production of little to no particulate matter. While we had no way of quantifying this, the difference between Sugar's relatively benign exhaust and that of an idling advertising truck down the street—this one happened to be looping the trailer for Hairspray on its side—was striking.
Although CNG generally costs 15 to 40 percent less than gasoline or diesel, the catch is that CNG-powered vehicles require more frequent rejuicing, because CNG contains only about a quarter of the energy by volume of gasoline. And only deep pocketed drivers need apply: Because of the higher cost of the fuel cylinders, CNG vehicles cost between $3,500 to $6,000 more than their gasoline-powered brethren. Of course, as the popularity of CNG vehicles catches on, vehicle prices should decrease also.
Now the emissions profile of chocolate, on the other hand, is a whole other post.