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Oxidative Stress from PM Emitted by Various Light-Duty Vehicle Engine Technologies and Fuels

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

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Oxidative Stress from PM Emitted by Various Light-Duty Vehicle Engine Technologies and Fuels

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

  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 PM chemistry PM OS Intro Emissions overview

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

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

  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) EST, 48(13): 7576-7583, 2014 PM chemistry PM OS Intro Emissions overview

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

  7. Overview of particulate emissions This study (log) Full VEDS database This study (linear) • 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) PM chemistry PM OS Intro Emissions overview

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

  9. ROS results • 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 higherthan gasoline • Per mile: • Diesel and Biodiesel UC cycle highest • Highway ROS still low • Ethanol, GDI lowerthan gasoline PM chemistry PM OS Intro Emissions overview

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

  11. ROS-elemental correlation (1/2) Among most abundant elements (ICPMS), six had r2 > 0.50: S, Cu, Ba, Cr, Sb, Sr PM chemistry PM OS Intro Emissions overview

  12. ROS-elemental correlation (2/2) S (0.89) Fe (0.11) (r2 in parentheses) diesel/biodiesel ROS > gasoline ROS higher r2 for elements in diesel but not gasoline Cu (0.78) PM chemistry PM OS Intro Emissions overview

  13. Conclusions 5 LDV vehiclesusing 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

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