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CRGAQS: Revised CAMx Results

CRGAQS: Revised CAMx Results

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CRGAQS: Revised CAMx Results

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  1. CRGAQS:Revised CAMx Results Presentation to the Gorge Study Technical Team By ENVIRON International Corporation December 6, 2006

  2. Today’s Presentation • Recap modeling performance issues • Describe latest CAMx simulations • Model and emission changes • Performance for PM and light scattering • Next Steps

  3. Modeling Issues • Episodes • August 10-22, 2004 • November 4-18, 2004 • Identified issues from sensitivity runs • Primary fine/coarse PM over predicted in both episodes • Dominating modeled light scattering • Windblown dust vs. fires? • Nope: construction + agricultural fugitive dust

  4. Modeling Issues • OC over predicted in both episodes • SOA is dominant in Aug (mainly biogenic) • POA (+EC) is dominant in Nov near Portland (wood smoke) • Why is modeled scattering nearly zero in mid-November in the Mt Zion area? • Easterly winds accelerate through Gorge and send Portland emissions offshore

  5. Modeling Issues • Why is modeled scattering so low at the eastern sites in November? • No speciated data at Gorge study sites • IMPROVE data on Nov 11 indicates dominance of NO3 and OC • OC, EC, and SO4 performance is good in east • NO3 is under predicted in east • We rely on modeled RH to generate the nitrate (complex process) • We use observed RH to translate nitrate mass to nitrate scattering (simple process)

  6. Revised Model Configuration • SOA • Historically under predicted by CMAQ and CAMx in the western U.S. (e.g., WRAP) • Attributed to the biogenic component • We employed a chemical improvement in CAMx for biogenic SOA • Same as put into CMAQ for the RPOs • Terpene 2-product mechanism: higher yields, higher volatility • Should reduce biogenic SOA

  7. Revised Model Configuration • Fugitive dust • 2 SMOKE problems: • WRAP speciation profiles caused a double-counting of OR/WA dust estimates • This also impacted OR/WA woodsmoke emissions • No county-level “canopy escape factor” was applied (as developed and applied in WRAP) • Both have been fixed and SMOKE re-run • Significant coarse PM reductions • Note: WRAP has chosen to completely disregard primary coarse PM predictions

  8. Performance Evaluation

  9. August Performance Evaluation Gorge Site Bscat East Portland

  10. August Performance Evaluation Wishram Bonneville Mt. Zion

  11. August Performance Statistics

  12. August Performance Evaluation

  13. August Performance Evaluation

  14. Gorge Study vs. IMPROVEAt Mt. Zion Organic and Elemental Carbon

  15. Gorge Study vs. IMPROVEAt Mt. Zion Sulfate and Nitrate

  16. August Summary • Overall good performance for • Total PM2.5 • Light scattering • Low SO4/NH4 and primary fine • Questionable Gorge measurements • NO3 insufficient to worry about • High carbon • SOA modification ineffective • What is underlying cause? • Model over predicts diurnal variation

  17. November Performance Evaluation Gorge Site Bscat Portland Eastern Gorge

  18. November Performance Evaluation Mt. Zion Bonneville Mt. Zion

  19. November Performance Statistics

  20. November Performance Evaluation

  21. November Performance Evaluation

  22. November Summary • Generally high total PM2.5 • Dominated by carbon and primary fine • Bifurcated performance for light scattering • Over predicted in Portland area: high carbon and primary fine • Under predicted in eastern Gorge: low SO4/NO3/NH4 • Need more humidity/clouds: • Generate more SO4 • Condense more NO3

  23. Next Steps • Recommendations: • Focus on August episode • 2018 Case • PSAT • “What-if” scenarios • Use model trends in relative sense to scale IMPROVE observations • Relegate November episode • Revisit with possible follow-on funding?