SALT LAKE CITY -- The idea is simple, if expensive. Less sulfur out of tailpipes means fewer red air days along the Wasatch Front.
Sen. Ralph Okerlund, R-Monroe, wants tier three gasoline in Utah cars as soon as possible, which means convincing the five refineries in Salt Lake and Davis Counties to upgrade their production.
"Tier 3 fuel is the one way we can clean up our air very quickly," Okerlund said.
Okerlund, sponsor of Senate Bill 102, would provide tax credits to refineries that transition to production of low sulfur gasoline.
Sulfur emissions are the primary mobile (vehicle-emitted) precursor to PM 2.5 particulates, which get trapped in valley inversions, making air unhealthy to breathe.
"If you put a lower sulfur content gasoline into a car, it can't emit a higher sulfur exhaust," said Dan Bammes of the Utah Foundation.
The EPA has mandated a transition to tier 3 production for all U.S. refiners, but small refiners are exempted until 2020. All of Utah's refineries are considered small by national standards, though when combined with two refineries in Wyoming, they provide 90 percent of Utah's gasoline.
"If we're actually able to do that, we clean up the air by 40 percent," Okerlund said.
Tier 3 is one of a pair of changes that should reduce auto emissions by as much as 80 percent.
The other change, Partial Zero Emission Vehicles, is a designation for cars that have a catalytic converter installed by the engine rather than at the end of the exhaust system. Those cars are available from all manufacturers, but are not required in Utah.