1. Implementation of the Particle & Precursor Tagging Methodology (PPTM) for the CMAQ Modeling System: Sulfur & Nitrogen Tagging 5 th Annual CMAS Conference Friday Center, UNC-Chapel Hill, NC 17 October 2006 Tom Myers, Sharon Douglas & Jay Haney ICF International, San Rafael, CA

2. Presentation Outline Conceptual overview of PPTM Implementation of PPTM for sulfur and nitrogen in the CMAQ model Testing & example results S tagging application for pulp & paper sector

3. Overview of PPTM: Concepts Emissions (or initial/boundary condition) species are tagged in the emissions (or IC/BC) files and continuously tracked throughout the simulation Tags can be applied to source regions, source categories, individual sources, initial conditions, and/or boundary conditions PPTM quantifies the contribution of tagged sources to simulated species concentrations & deposition Base simulation results not affected by tagging

4. Overview of PPTM: Concepts Within the model, tagging is accomplished by the addition of duplicate species (e.g., SO2_t1, SO2_t2) Tagged species have the same properties and are subjected to the same processes (e.g., advection, chemical transformation, deposition) as the actual species Mercury (Hg), sulfur (S), and nitrogen (N) tagging completed; tagging for elemental carbon (EC) and organic carbon (OC) under development/testing

5. Example Uses of PPTM for Sulfur and Nitrogen Determine the contribution of SO2 emissions from an individual source, group of sources, or source category (e.g., electric generating units (EGUs), pulp and paper facilities) to sulfate and overall PM2.5 concentrations Quantify/compare the contribution of NOx emissions from transportation sources, area sources (e.g., wood burning stoves) & offroad sources (e.g., IC engines, construction equipment)

6. Implementation of PPTM for CMAQ: Sulfur & Nitrogen CMAQ version 4.5 Tagged S elements include: SO2, ASO4I, ASO4J, SULF (for internal tracking) Tagged N species include: ANH4I, ANH4J, ANO3I, ANO3J, NO, NO2, NO3, N2O5, HNO3, HONO, PNA, PAN, NTR, NH3

7. Implementation of PPTM for CMAQ: Sulfur & Nitrogen Key considerations/assumptions: Linear processes simulated directly Potentially non-linear processes calculated for total species and apportioned to tags Additional terms from some processes saved to ensure proper allocation Gas-phase chemistry routines have additional production & loss terms added; NO, NO2, NO3, N2O5 changes apportioned based on NOx totals for each tag

8. Implementation of PPTM for CMAQ: Sulfur & Nitrogen Key considerations/assumptions: Other N species calculated with additional chemistry terms; adjusted so net production/loss for sum of tags matches that for the whole Simulation calculates the overall species value as the sum of all tags; tags must be defined to add up to the whole

9. Implementation of PPTM for CMAQ: Sulfur & Nitrogen CPU requirements increased by approximately 15% for 3 S tags and 50% for 3 N tags Documentation/user’s guide available from EPA or ICF as follows: Douglas, S., T. Myers and Y. Wei. 2006. “ Implementation of Sulfur and Nitrogen Tagging in the Community Multiscale Air Quality (CMAQ) Model.” Prepared for EPA, OAQPS, Research Triangle Park, NC. ICF International, San Rafael, California (06-076).

10. Example Sulfur Tagging Results

11. CMAQ PPTM: Contribution to Monthly Average Sulfate

14. CMAQ PPTM: Site-specific SO4 Contributions (IMPROVE Sites) ugm-3 CMAQ simulated monthly average contribution to sulfate from three example EGU facilities.

15. Sulfur Tagging Application for the Pulp & Paper Sector Based on CAIR 2010 modeling & emission inventory 1 month simulation period (July) (Annual simulation ongoing) Tags applied for 10 pulp & paper sources and IC/BCs

16. CMAQ PPTM: Monthly Average Sulfate for July 2010

17. CMAQ PPTM: Contribution to Monthly Average Sulfate

19. CMAQ PPTM: Site-specific SO4 Contributions (IMPROVE Sites) ugm-3 CMAQ simulated monthly average contribution to sulfate from regional pulp & paper facilities.

20. CMAQ PPTM: Site-specific SO4 Contributions (Urban Sites) ugm-3 CMAQ simulated monthly average contribution to sulfate from regional pulp & paper facilities.

21. CMAQ PPTM: Site-specific SO4 Contributions (Urban Sites) ugm-3 CMAQ simulated monthly average contribution to sulfate from regional pulp & paper facilities.

22. Example Nitrogen Tagging Results

23. Example CMAQ PPTM Nitrogen Tagging Results: Great Smoky Mtns NH4 NO3 NOx

24. Example CMAQ PPTM Nitrogen Tagging Results: Great Smoky Mtns NH4 NO3 NOx

25. Summary of CMAQ PPTM Status and Next Steps PPTM has been successfully implemented in the CMAQ model for S, N (and Hg) and quantifies the contribution of tagged sources to simulated PM Application & interpretation of results is straightforward (no hidden assumptions) Initial test results indicate that numerical effects (uncertainties) are small, compared to contribution estimates Next steps include Complete implementation for OC & EC Add OPTM (for ozone)