1. Western States Air Quality Study Background Air Quality Modeling University of North Carolina (UNC-IE) ENVIRON International Corporation (ENVIRON) May 13, 2015 Western States Air Quality Study Intermountain West Data Warehouse

2. 3SAQS/WSAQS Modeling Create a standardized regional modeling platform for NEPA and other Western U.S. air quality studies Cooperators at the NPS, USFS, BLM, EPA Region 8, States of CO, UT, WY Populate a centralized modeling data repository USBG Context – Project is focused on rural ozone – Quantify regional background air quality – Understand influence of transport on Western U.S. air quality – Source apportionment

3. 3SAQS/WSAQS Modeling 20122013 2014 OCT 2012 Pilot Project Start NOV-DEC 2012 CO, UT, WY 2008 EI Analysis and Evaluation FEB 2014 3SAQS Monitoring Network Report OCT 2013 WRF 2011 Sensitivities AUG 2014 CAMx 2008b, WRF 2011, 2011 Oil & Gas EI, 2011a Emissions JUL 2014 Final 2008 Emissions OCT 2014 CAMx 2011a MPE SEP 2014 SMOKE 2011a JUN 2012 Emissions VOC Reactivity Analysis FEB-MAY 2012 2008 EI Modeling MAR-JUN 2014 2011 EI Modeling NOV 2014- APR 2015 CAMx 2011 Sensitivities 2015 AUG 2012 CAMx 2008a JAN 2013 EI Improvement Meetings With CO, UT, WY

4. 4 WSAQS Project Timeline 2015 DEC 2014- APR 2015 Base11a MPEv2 JAN-MAR CMAQ Base11a JAN-APR WRF Winter Modeling Configuration MAR-JUN 2011b Emissions Development AUG 2011b CAMx MPE JUN-JUL 2011b CAMx Modeling Early SEP 2015 Technical Comm Meeting SEP 2015 Release CAMx 2011b NOV Prelim 2014 Platform Release April 29-30 Tech Comm Call MAY Base2011a Platform Release; MOVES and Winter O3 CAMx Complete APR Phase II O&G EI Release MAY-AUG 2014a WRF and SMOKE JAN 21 Governing Board Meeting FEB 25, 2015 Technical Comm Meeting JUL 2015 Technical Comm Call

5. WSAQS U.S. Background Simulation Objectives – Use a regional Chemistry-Transport model to estimate U.S. background (USBG) air quality in the West Design – CAMxv6.10 Annual 2011 36/12/4-km – All U.S. anthropogenic emissions removed – Downscale NCAR MOZART-GEOS5 GCM to CONUS36-km BCs with CB6r2 chemistry

6. Urban (AQS) Rural (CASTNET) WSAQS USBG Simulation CAMx 12-km Monthly Mean Daily Max 8-hr O 3 (MDA8)

7. Seasonal Averages at CASTNET Monitors April 2011: USBG – Base April 2011: Daily Max Surface O3 WSAQS USBG Simulation CAMx 12-km Monthly Mean MDA8 CO CASTNET Sites

8. WSAQS USBG Simulation CAMx 12-km Monthly Mean MDA8 Domain CASTNETAQS AZ45.743.9 CA42.738.7 CO47.245.6 IDN/A42.0 MTN/A40.9 NMN/A46.2 NV46.143.6 ORN/A36.3 UT44.543.3 WA38.638.5 WY45.242.7 Results – Annual average domain-wide background MDA8 at CASTNET = 43.7 ppb AQS = 42.0 ppb – Annual maximum domain-wide background MDA8 at CASTNET = 79.9 ppb (April) AQS = 83.5 ppb (May) Annual Average MDA8 CAMx 12-km USBG (ppb)

9. Unrealistically high background contribution to total PM 2.5 at IMPROVE sites. WSAQS USBG Simulation CAMx 12-km Monthly Mean Total PM 2.5

10. 10 3SAQS Base 2011a MPE PM 2.5 Performance Boundary Conditions MOZART BCs found to be contributing too much dust to the CAMx simulation Replacing MOZART with GEOS-Chem BCs drastically improves Total PM 2.5 model performance 4-km domain IMPROVE spring NMB: MZBC = 155% GCBC = -8.5% 3SAQS BC Sensitivity Wiki* 3SAQS BC Sensitivity Wiki *http://vibe.cira.colostate.edu/wiki/wiki/1043/bc-sensitivity-modeling-results

11. Boundary Condition Sensitivity Tests Objectives – Investigate regional model performance issues related to boundary conditions (BCs) downscaled from global chemistry models (GCMs) – Identify systematic problems in the available GCM BCs – Produce recommendations for how to use GCM BCs for regional modeling in the West – Find a best-performing BC dataset for simulation 2011b Design – Downscale MOZART, GEOS-Chem, and AM3 to CONUS36-km BCs with CB6r2 chemistry – Winter/summer simulations with CAMx to evaluate the influence of the different BCs on model performance

12. 12 WSAQS BC Sensitivities CAMx 12-km January 2011 Hourly O 3 CASTNET AQS Rural (CASTNET) – AM3 is high – MZ and GC are comparable during the day – GC low at night Urban (AQS) – AM3 is high – GC is the lowest of the three and best match to obs

13. 13 WSAQS BC Sensitivities CAMx 12-km July 2011 Hourly O 3 CASTNET AQS Rural (CASTNET) and Urban (AQS) – No significant difference between any of the GCMs

14. 14 WSAQS BC Sensitivities CAMx 12-km IMPROVE Daily Total PM 2.5 January July January – CAMx overestimates total PM2.5 with all GCMs – MZ is incrementally worse than others July – Overestimates with MZ – Underestimates with GC and AM3

15. 15 Cap MZBC dust concentrations (FCRS and CCRS) and zero-out sea salt – Besides dust, MZBC produces lower biases for inorganic PM 2.5 and O 3 than the other GCM BCs CAMx TOPCON simulation Perform annual 2011 36/12 km BC sensitivity test – Annual MPE to make sure no new issues related to BC – Adopt BCs for 2011b platform by end of May/early Jun WSAQS BC Sensitivities 2011 Western Modeling Platform: Next Steps

16. 16 Need for a detailed evaluation of GCM results in the context of downscaling to Western regional modeling applications – Conduct this evaluation before significant efforts to evaluate regional modeling – Regional models should be part of the GCM evaluation suite What role can the GCM community play in advising regional modelers on how to use GCM data in downscaled applications? WSAQS BC Sensitivities 2014 Western Modeling Platform: Looking Forward