Change in Air Quality Impacts Associated with the Use of E15 Blends Instead of E10

LCA.6091.94.2014 July 2014

Prepared by:

Stefan Unnasch Ashley Henderson

DISCLAIMER

This report was prepared by Life Cycle Associates, LLC for Americans United for Change. Life

Cycle Associates is not liable to any third parties who might make use of this work. No warranty

or representation, express or implied, is made with respect to the accuracy, completeness, and/or

usefulness of information contained in this report. Finally, no liability is assumed with respect to

the use of, or for damages resulting from the use of, any information, method or process

disclosed in this report. In accepting this report, the reader agrees to these terms.

ACKNOWLEDGEMENT

Life Cycle Associates, LLC performed this study under contract to Americans United for

Change.

Contact Information:

Stefan Unnasch

Life Cycle Associates, LLC

1.650.461.9048

unnasch@LifeCycleAssociates.com

www.LifeCycleAssociates.com

Recommended Citation: Unnasch, S. and A. Henderson, (2014). Air Quality Impacts Associated

with the Use of E15 Blends Instead of E10. Life Cycle Associates Report LCA.6091.94.2014.

Prepared for Growth Energy.

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Contents

Terms and Abbreviations ............................................................................................................... iii

Executive Summary ........................................................................................................................ v 1. Introduction ............................................................................................................................. 1

1.1 Energy Policies ................................................................................................................. 1 1.2 Study Objectives .............................................................................................................. 1 1.3 Ethanol Blend Research ................................................................................................... 2

1.4 Approach .......................................................................................................................... 3 2. Background: Fueling with E15 ............................................................................................... 4

2.1 What is E15? .................................................................................................................... 4

2.2 Transport of E15............................................................................................................... 5 2.3 Storage and Dispensing of E15 ........................................................................................ 5 2.4 What vehicles can use E15? ............................................................................................. 6

2.5 Drivability Testing ........................................................................................................... 7 3. Vehicle Air Emissions and Related Health Impacts ............................................................... 7

3.1 How do exhaust emissions form? .................................................................................... 8

3.1.1 Carbon Monoxide (CO) ............................................................................................ 8 3.1.2 Hydrocarbons (HC) ................................................................................................... 8

3.1.3 Nitrogen Oxides (NOx) ............................................................................................. 8 3.1.4 Particulate Matter (PM) ............................................................................................ 8 3.1.5 Toxic Pollutants ........................................................................................................ 9

3.1.6 VOCs and Ground Level Ozone ............................................................................... 9 3.1.7 Greenhouse Gases ..................................................................................................... 9

3.2 Air Pollutant Human Health Impacts ............................................................................... 9 4. Changes in Emissions from Use of Ethanol Blended Fuels ................................................. 13

4.1 Age of vehicle ................................................................................................................ 13 4.2 Fuel Composition ........................................................................................................... 14

4.2.1 Oxygen Content ...................................................................................................... 16 4.2.2 Heat of Vaporization ............................................................................................... 17 4.2.3 Octane Number ....................................................................................................... 17 4.2.4 Vapor Pressure ........................................................................................................ 17

4.3 Blending Technique ....................................................................................................... 18 4.4 Evaporative Emissions ................................................................................................... 19 4.5 Spills ............................................................................................................................... 19 4.6 Fuel Economy Impacts ................................................................................................... 20

5. Findings of Existing Studies of Ethanol Blend Exhaust Emissions ..................................... 22 5.1 Carbon Monoxide Findings ............................................................................................ 22 5.2 Nitrogen Oxide Findings ................................................................................................ 22

5.3 Carbonyl Findings .......................................................................................................... 22 5.4 Aromatic Compounds .................................................................................................... 23 5.5 Particulate Matter ........................................................................................................... 23

6. Meta-analysis of Emission Test Data ................................................................................... 25 6.1 Normalization ................................................................................................................. 25

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6.2 Toxicity Air Contaminants ............................................................................................. 26

6.2.1 Polycyclic Aromatic Hydrocarbons (PAHs) ........................................................... 26 6.2.2 Ozone Potential ....................................................................................................... 26

6.3 Results ............................................................................................................................ 27

6.3.1 NOx, CO, and NMHC ............................................................................................. 28 6.3.2 Weighted Toxic Emissions ..................................................................................... 31 6.3.3 Greenhouse Gas Emissions ..................................................................................... 32 6.3.4 Statistical and Uncertainty Analysis ....................................................................... 32

7. Discussion and Conclusions: Net Effects of Changing from E10 to E15............................. 33

Appendix A. Federal Emission Standards .................................................................................... 37 Appendix B. Normalized Emissions ............................................................................................. 41 Appendix C. Uncertainty Analysis ............................................................................................... 44 References ..................................................................................................................................... 47

Tables

Table 1.1 Summary of Prior Ethanol Blending & Emissions Research ......................................... 3

Table 2.1. Description of Ethanol Properties .................................................................................. 5 Table 3.1. Air Emission Human Health Impacts .......................................................................... 11 Table 3.2. EPA IRIS and OEHHA Unit Risk Factors .................................................................. 12

Table 4.1. Emission control technologies and design features ..................................................... 14 Table 4.2. Fuel Properties of Pure Ethanol vs. Pure Gasoline ...................................................... 15

Table 4.3. Fuel Composition and Chemical Properties of Gasoline/Ethanol Blends ................... 16 Table 4.4. Calculation of Ethanol Blend Energy Content ............................................................ 21 Table 4.5. Energy Content of Ethanol Blends .............................................................................. 21

Table 5.1. Summary of Individual Emission Study Results ......................................................... 24

Table 4.7. Ozone potential for selected chemicals ...........................................................