1. 1 AIR QUALITY AND ETHANOL Gary Z. Whitten

2. 2 INTRODUCTION Ethanol impacts both positive and negative Ethanol similar to but not MTBE Trade-off’s can be complex Not readily acceptable due to  Regulations  Agencies  Oil companies  And sometimes environmental groups

3. 3 Carbon Monoxide, Ozone, Toxics, and PM CO makes ozone Toxics are closely regulated and adjusted in RFG PM needs more recognition

4. 4 Carbon monoxide makes ozone 1974 paper “just CO and NOx might exceed ozone standard.” 1988 testimony “1 pound waiver mainly due to CO reduction by ethanol.” 1998 NRC study “credit for CO reduction should be in RFG.”

5. 5 Toxics are closely regulated in RFG Ethanol can reduce benzene by 30 percent Dilution Octane substitute for aromatics Cleaner burning Refiners often can adjust benzene for RFG Acetaldehyde increased by ethanol, but several studies show this is not a problem

6. 6 PM needs more recognition Science of PM rapidly emerging PM can be primary or secondary Ethanol significantly reduces both Secondary (man-made)may be essentially all from aromatics Ethanol impact similar to benzene

7. 7 Ozone Trade-offs CO reduction equal to at least 3% of VOC This is for RFG going from 2% to 3.5% oxygen For non-oxy the full credit could be 7% Aggressive driving, high emitters, old cars, and off-road engines also show VOC benefits Unfortunately, regulations based mainly on data from low-emitting vehicles show much VOC benefit

8. 8 Trade-offs (Cont.) Recent data (1999) show 63% of CO and 47% of VOC coming from 10% of vehicles ARB tests show aggressive driving (REP05) Ethanol (vs MTBE) showed 3% benefit in normal driving (FTP) but 10% when REP05 data included. Complex Model for RFG and ARB model both all based on FTP (no REP05 data)

9. 9 Trade-offs (cont.) EPA tests on 36 vehicle fleet (half higher emitters) show 6% CO reduction and 4% VOC reduction with ethanol (vs, MTBE), but all the benefits came from the higher emitters. Note only FTP data here (no REP05) Grid model tests show CO major (33% of ozone) impact Exhaust VOC more important than evaps.