Removing particulate matter by using low-sulfur diesel is very expensive. Low-sulfur is expensive in Alaska because of high transportation costs and high distribution costs. Generally, low-sulfur diesel must be kept separate from standard diesel. Because of this requirement of segregating low-sulfur diesel from other diesel, distributors would have to install separate distribution systems. This would mean new tanks, piping, and pumps, and in some cases, new trucks.
Alaskan refineries refine North Slope crude, a crude oil that is naturally high in sulfur.
Alaskan refineries do not have the equipment to remove enough sulfur from the crude to make low-sulfur diesel fuel. Parts of Canada have a climate similar to Alaska's. The transportation costs would be at least as expensive from Canada as from the Lower 48. The distribution costs would be exactly the same regardless of where the fuel comes from. No, this exemption will not make any difference in Alaska's non-attainment areas.