Tier 3 refers to strengthened emissions standards that reduce pollutants from both gasoline and vehicles. Together, these vehicle and fuel standards will reduce emissions of VOCs and NOx—the main contributors to unhealthy air days in Utah—by 80 percent. That means it would take five Tier 3 cars to equal the pollution of just one older Tier 2 car. Tier 3 fuel alone will reduce vehicle emissions by roughly 7 to 11 percent even in older or more polluting cars. This is because Tier 3 fuel has, on average, just 10 parts per million of sulfur, down from the 30 that Tier 2 required.

So far Chevron, Marathon, Silver Eagle, and Sinclair have committed to producing Tier 3 fuel at their Utah-serving refineries. The state's other refineries have expressed an interest in making the conversion in the coming years. Utah gas stations carrying fuel from these refineries will generally provide Tier 3 fuel at the pump. Want to know where to purchase Tier 3 fuel? The locations of gas stations carrying Tier 3 gas in Utah can be found here.