1. Oxidative Stress from PM Emitted by Various Light-Duty Vehicle Engine Technologies and Fuels Chris Ruehl, John Collins, Satya Sardar, Chandan Misra, & Jorn Herner 1 CA Air Resources Board Mobile Source Air Toxics workshop February 18, 2015

2. Today’s talk 1. Introduction / background material 2. Overview of emissions by all 8 vehicle configurations 3. Oxidative Stress (OS) induced by emitted PM 4. Relationship between OS and PM chemistry 2 IntroEmissions overview PM OS PM chemistry

3. Fuels and vehicles tested 5 fuels: 1)Gasoline 2)E85 (85% Ethanol) 3)CNG (Natural Gas) 4)Diesel 5)Biodiesel 3 IntroEmissions overview PM OS PM chemistry 5 vehicles, w/mileage: 1)1998 Mercedes 420SEL (“High-emitter”), 240k 2)2008 Chevy Impala flex (E85/gasoline), 35k 3)2010 VW Jetta GDI, 10k 4)2007 Honda Civic CNG, 15k 5)2012 Chevy Silverado (diesel), 10k UC cycle (hot and cold start), Highway cruise

4. 4 8 total LDV configurations G asoline, E 85: 2008 Chevy Impala B iodiesel, D iesel: 2012 Chevy Silverado (w/DPF) C NG: 2007 Honda Civic GD I, GDI+GP F : 2010 VW Jetta H igh-emitter: 1988 Mercedes 420SEL B: Biodiesel C: CNG D: Diesel E: Ethanol (E85) F: GDI + GDF G: Gasoline (PFI) H: “High-emitter” I: GDI IntroEmissions overview PM OS PM chemistry

5. 5 ROS assay ROS = “Reactive Oxygen Species” In vitro assay using rat macrophage cells Done at UWM (Martin Shafer) Filters are extracted in DI water: sonication, overnight shaking, sonication (all dark) IntroEmissions overview PM OS PM chemistry EST, 48(13): 7576-7583, 2014

6. Overview of gaseous emissions 6 IntroEmissions overview PM OS PM chemistry study This study Full VEDS database (Haagen-Smit Lab)

7. Overview of particulate emissions 7 IntroEmissions overview PM OS PM chemistry Full VEDS database study (log) This study (log) Median PM emitted per mile: High emitter > GDI > PFI > GDI + GPF > E85 > Biodsl > CNG > Dsl Biodiesel and Diesel are skewed towards larger EFs (probably regeneration) study (linear) This study (linear)

8. PM mostly OC/EC 8 IntroEmissions overview PM OS PM chemistry Among all 8 LDVs, 67±5% of gravimetric PM was detected as OC + EC GDI had most EC (78±5% of TC) High-emitter had most OC E85 highest OC/TC (78±5%) CNG EC below MDL All LDVs GDI High-emitter

9. 9 Per mg: Diesel and Biodiesel highest and most variable – probably due to regeneration Warm start ROS similar to or greater than cold start Highway ROS lower for all LDVs Ethanol, GDI higher than gasoline Per mile: Diesel and Biodiesel UC cycle highest Highway ROS still low Ethanol, GDI lower than gasoline ROS results IntroEmissions overview PM OS PM chemistry

10. 10 Sonicated aqueous extracts were run w/ and w/o filtering (0.2 μm polypropylene) ROS response decreased with filtering for most vehicles GDI: 99% reduction ROS removed by filtering extracts IntroEmissions overview PM OS PM chemistry Diesel – greater WSOC contribution E85 – only UC cold start ROS removed by filtration, and only 40% toxicity due more to WSOC

11. 11 ROS-elemental correlation (1/2) IntroEmissions overview PM OS PM chemistry Among most abundant elements (ICPMS), six had r 2 > 0.50: S, Cu, Ba, Cr, Sb, Sr

12. 12 ROS-elemental correlation (2/2) IntroEmissions overview PM OS PM chemistry diesel/biodiesel ROS > gasoline ROS higher r 2 for elements in diesel but not gasoline Fe Fe (0.11) S S (0.89) Cu Cu (0.78) (r 2 in parentheses)

13. 13 Conclusions 5 LDV vehicles using 5 fuels tested  8 LDV vehicle configurations Although PM was greatest in gasoline LDVs, PM was skewed high for diesel ROS per mile was greatest for diesel/biodiesel E85, GDI ROS greater than PFI per PM mass, but less than PFI per mile Filtering extracts removed much of the ROS activity: 99% for GDI, but much less (<50%) for diesel and ~0% for warm E85