1. Evolution and Air Quality Benefits of Arizona Cleaner Burning Gasoline Essential Services Task Force January 5, 2004 Ira Domsky Deputy Director Air Quality Division

2. Overview Gasoline properties and automobile emissions History of CBG standards Air quality benefits

3. Gasoline Properties and Emissions Pollutants of Concern Carbon Monoxide Hydrocarbons – evaporative and tailpipe Oxides of Nitrogen Hazardous Air Pollutants  Benzene  Butadiene  Aldehydes  Other products of incomplete combustion

4. Gasoline Properties and Emissions Gasoline Properties Octane or anti-knock index Volatility Distillation “curve” Oxygen Sulfur Aromatic hydrocarbons Olefins Benzene

5. Gasoline Properties and Emissions Always regulated for driveability (poor driveability results in high emissions) Octane Volatility Distillation Regulated specifically for emissions control All the rest

6. Evolution of CBG Standards Common theme: Many changes to gasoline standards adopted in Maricopa County have been driven by citizen lawsuits under the Clean Air Act Some changes were fostered by enlightened self-interest: Achieving attainment was good for business as well as public health

7. Evolution of CBG Standards Why gasoline standards are attractive emission control strategies Emission reductions are relatively large Automobiles account for the majority or a plurality of pollution No changes to engines or other technology are necessary Reduces emissions for all vehicle trips Everyone who uses gasoline pays

8. Evolution of CBG Standards YearChange Pollutants 1988 Oxygenated fuels adopted in nonattainment area CO 1991 Oxygen content increased, new RVP standards CO, HC 1992 County-wide for oxygenated fuels CO 1993 Wintertime RVP reduction CO 1993 Oxygen content increased & RVP decreased again CO 1995 Oxygenated fuels control period reduced - 1996 Gov. Symington opts-in to federal RFG program HC/NOx 1997 Arizona CBG standards adopted HC/NOx 1998 Wintertime CARB 2 adopted; Area A expanded CO 2000 Summertime minimum oxygen standard repealed -

9. Air Quality Benefits Cumulative Improvements SeasonPollutant Emissions Reductions (tons/day) Percent of Nonattainment Area Emissions Winter Carbon Monoxide 446.8% Summer Hydrocarbons 298.9% Oxides of Nitrogen 72.1%

10. Air Quality Benefits Standard

11. Air Quality Benefits Standard

12. Air Quality Benefits