1. Application of the CMAQ Particle and Precursor Tagging Methodology (PPTM) to Support Water Quality Planning for the Virginia Mercury Study 6 th Annual CMAS Conference Chapel Hill, NC 1-3 October 2007 Presented by Sharon Douglas ICF International, San Rafael, CA

2. Co-Authors: Tom Myers Yihua Wei Jay Haney Mike Kiss Patty Buonviri ICF Virginia DEQ

3. Presentation Outline Background & objectives Overview of CMAQ/PPTM Application of CMAQ/PPTM modeling for the Virginia Mercury Study

4. Background Atmospheric deposition of mercury is a source of mercury contamination in surface waters In the U.S., more than 8,500 bodies of water have been identified as mercury impaired Within Virginia, fish consumption advisories have been issues for several bodies of water located primarily along the coastal plain susceptible to mercury methylation & bioaccumulation of mercury in fish

5. Virginia Mercury Study Air Quality Modeling Objectives Review & update the Virginia mercury point source inventory Prepare “conceptual description” of mercury deposition characteristics for Virginia Conduct air quality modeling to simulate and quantify the contribution of regional and local emissions, and to provide information for TMDL assessments Evaluate the effectiveness of future national and state control measures to meet water quality goals

6. Mercury Deposition Modeling Approach: Baseline Modeling 2001 Meteorological Inputs2002 Criteria Pollutant & Mercury Emissions Community Multiscale Air Quality (CMAQ) Model, Version 4.6 AERMOD Gaussian Model CMAQ Performance Evaluation CMAQ Sensitivity Analysis CMAQ Particle & Precursor Tagging Methodology (PPTM) Identification of Sources with Significant Local Contributions AERMOD Sensitivity Analysis Assessment of Global, National, Regional, and Source-Specific Contributions

7. Mercury Deposition Modeling Approach: Future-Year Modeling 2001 Meteorological Inputs Future-Year Criteria Pollutant & Mercury Emissions 2010, 2015 & 2018 CMAQ, Version 4.6 w/PPTM AERMOD Expected Future Changes in Local Contributions Assessment of Future Control Measure Effectiveness Future-Year Projections Future-Year Mercury Contribution Analysis Information for Water Quality Modeling, TMDL…

8. CMAQ Version 4.6 w/Mercury Three species: elemental mercury (Hg 0 ), reactive gaseous mercury (RGM or Hg 2+ ), and particulate mercury (PHg) Gaseous & aqueous reactions involving mercury (Bullock & Breme, 2002) Recent enhancements include: improved dry deposition algorithm & natural emissions

9. Overview of the CMAQ Particle & Precursor Tagging Methodology (PPTM) PPTM can be applied for all PM species and for mercury (OPTM for ozone) 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, and/or IC/BCs PPTM quantifies the contribution of tagged sources to simulated species concentrations & deposition

10. Overview of PPTM For mercury, tagged elements include HG, HGIIGAS, HGIIAER, APHGI, APHGJ Within the model, tagging is accomplished by the addition of duplicate species (e.g., HG_t1, HG_t2) Tagged species have the same properties and are subjected to the same processes (e.g., advection, chemical transformation, deposition) as the actual species Base simulation results not affected by tagging

11. Application of CMAQ/PPTM for the Virginia Mercury Study PPTM #1 Tag 1: All anthropogenic Hg sources in VA Tag 2: All other Hg sources in the 12-km grid PPTM #2 Tag 1: EGU sources in VA Tag 2: Other EGU sources in the 12-km grid Tag 3: All other Hg sources in the 12-km grid

12. Virginia Mercury Study CMAQ Modeling Domain 36 km 12 km

13. CMAQ Base Results: Total Hg Deposition Results shown here are for July

14. CMAQ Base Results: Wet & Dry Hg Deposition Results shown here are for July DryWet

15. Results for PPTM#1: Total Hg Deposition Results shown here are for July VAOther

16. Regional Mercury Emissions Based on 2002 VDEQ and NEI Version 3 emissions

17. Results for PPTM#2: Total Hg Deposition Results shown here are for July VA EGUOther EGU

18. Results for PPTM#2: Total Hg Deposition Results shown here are for July Other

19. Summary CMAQ/PPTM can be used to track the fate of mercury emissions from selected sources & quantify their contribution to CMAQ-derived concentration and deposition estimates Preliminary results for the Virginia Mercury Study indicate that Wet & dry deposition vary with meteorology and have distinctly different patterns Both local and regional sources contribute to Hg deposition in VA Transport from outside of the 12-km domain is an important contributor to mercury deposition in VA