1. Trans-Pacific Chemical Transport of Mercury: Sensitivity Analysis on Asian Emission Contribution to Mercury Deposition in North America Using CMAQ-Hg C.-J. Lin* 1, P. Pongprueksa 1, T. Vanjani 1, T. C. Ho 1, H. Chu 1, C. Jang 2, T. Braverman 2, D. G. Streets 3, and J. S. Fu 4 1 College of Engineering, Lamar University, Beaumont, TX 2 USEPA OAQPS, Research Triangle Park, NC 3 ANL Decision & Information Sciences Division, Argonne, IL 4 Dept. Civil & Environmental Engineering, Univ. of Tennessee, Knoxville, TN 5 th Annual CMAS Conference Research Triangle Park, NC October 17, 2006

2. Mercury is a global pollutant Elemental mercury has long atmospheric lifetime - long range transport likely Recent concerns of “mercury export” from Asia (Jaffe et al., 2005) Trans-Pacific transport of criterion pollutants has been identified (Jang et al., 2003; 2004) Why Inter-continental Transport of Mercury?

3. Atmospheric Mercury Properties

4. Objectives Investigate trans-Pacific transport of gaseous elemental mercury (GEM) to North America Assess mercury deposition in North America caused by the long-range transport of GEM Study the source contribution of mercury deposition in North America

5. Simulation Approaches Meteorology – ICAP meteorological fields (USEPA) for Year 2001 Emission Inventory – ICAP criterion pollutant EI with re-projected global mercury EI Model – Research version of CMAQ_Hg by USEPA (R. Bullock). No treatment of GEM deposition and 50/50 speciation of RGM/PHg as oxidation products (before v4.5.1) IC/BC – regridded from Harvard data (Jacobs & Fu) Annual sensitivity simulations performed

6. Initial and Boundary Conditions Hg(0) Hg(II) Hg(P) Hg(T) From Harvard GEOS-CHEM Global Model in Year 2001

7. Emission Sources Anthropogenic –Fuel combustion –Waste incineration –Industrial metal processing (including Hg mining), etc. Emission from natural processes (Natural) –Volcano eruption, weathering, etc –Emission from vegetation, soils and water bodies – Fire emission Re-emission –Caused by past mercury emission and deposition – Biotic and abiotic processes cause reduction of deposited Hg(II) back to volatile Hg o – Usually indistinguishable from surface exchange

8. Emission Preparation for ICAP Simulations Anthropogenic sources –Regridded from global Hg emission inventory (Pacyna et al., 2003; 2006) –Emission in China revised according to Streets et al. (2005) Natural sources / Re-emission –Regridded from AER global natural/re-emission (Seigneur et al., 2004)

9. Trans-Pacific Transport of Hg As part of USEPA ICAP project work

10. Annual Average Concentration Hg(0)Hg(II) Hg(P) Hg(T)

11. Total Annual Dry Deposition Hg(0) Hg(II) Hg(P) Hg(T)

12. Total Annual Wet Deposition Hg(0) Hg(II) Hg(P) Hg(T)

13. Total Annual Deposition Hg(0) Hg(II) Hg(P) Hg(T)

14. 2001 MDN Total Hg Wet Deposition Source: http://nadp.sws.uiuc.edu/mdn, 2006 13 sites selected for verification based on data completeness & precipitation.

15. Model vs. MDN Wet Deposition

16. Modeled Annual Wet Deposition

17. Source Contribution to Wet Deposition

18. Total Annual (Dry + Wet) Deposition

19. Sources Contribution to Total Deposition

20. CMAQ Results for 2001 ICAP Domain Oth Nat.

21. Trans-Pacific transport events of Hg identified in 2001 (Mar.-Apr. & Oct.-Nov.), contributing 0.1-0.2 ng/m 3 GEM in west coast regions. Chemistry forcing and/or out-of-boundary transport (IC/BCs) dominate Hg deposition in North America. Although the direct forcing of Asian Hg emissions on the US deposition is small, their contribution to global background cannot be neglected. Local emission can contribute significantly to both dry and wet depositions even with the coarse ICAP domain grids. Anthropogenic Hg emission from North America has negligible impact on total Hg deposition in the ICAP domain. Asian anthropogenic emission contribute much greatly to the concentration and deposition. Conclusions

22. Acknowledgements USEPA – OAQPS (RTI subcontract No. 3-93U-9606). Texas Commission on Environmental Quality (TCEQ work order No. 64582-06-15). Steve Lindberg, University of Nevada at Reno. Russ Bullock, USEPA. Jocelyn Mellberg, TCEQ. Xinbin Feng, Chinese Academy of Sciences. Christian Seigneur, AER