1. DEVELOPMENT AND APPLICATION OF MADRID: A NEW AEROSOL MODULE IN MODELS-3/CMAQ Yang Zhang*, Betty Pun, Krish Vijayaraghavan, Shiang-Yuh Wu and Christian Seigneur Atmospheric and Environmental Research, Inc., San Ramon, CA Spyros N. Pandis Carnegie-Mellon University, Pittsburgh, PA Mark Z. Jacobson Stanford University, Stanford, CA Athanasios Nenes Georgia Institute of Technology, Atlanta, GA John H. Seinfeld California Institute of Technology, Pasadena, CA EPA Models-3/CMAQ Workshop, October 27-29, 2003 * Current address: North Carolina State University

2. Presentation Outline Background –Development of CMAQ-MADRID –CMAQ vs. CMAQ-MADRID 3-D Application –Application for SCAQS Episode –Sensitivity Study –Performance Evaluation Summary

3. Development of CMAQ-MADRID Model for Aerosol Dynamics, Reaction, Ionization, and Dissolution –Review of thermodynamic modules –Review of aerosol dynamics modules –Selection and integration of the modules 3-D Host Model - EPA Models-3/CMAQ –Evaluation of 3-D models (SAQM, MAQSIP, CMAQ, and CAMx) –Selection protocol (sciences, computation, ease-of-use, modularity, documentation, technical support and community status) Incorporation of MADRID and CMU Aqueous Module into CMAQ –Preserves features of EPA Models-3/CMAQ –Advanced aerosol and cloud modules –Provided to EPA in December 2002

4. CMAQ vs. CMAQ-MADRID: PM Treatment Models-3/CMAQ Size representation Modal (3 modes) Inorganic species NH 4 +, SO 4 =, NO 3 -, Na +, Cl - Equilibrium MARS-A, ISORROPIA Coagulation Modal approach Nucleation Absolute rate Condensation Modal approach Mass transfer Full equilibrium Dry deposition Resistance transfer SOA formation Irreversible absorption (6 precursors) (Pandis et al., 1992) or reversible absorption (6 precursors) (Schell et al., 2001) CMAQ-MADRID Sectional (2 or multiple sections) NH 4 +, SO 4 =, NO 3 -, Na +, Cl - ISORROPIA Not treated Relative rate Moving-center approach CIT equilibrium and CMU hybrid Revised flux approach MADRID 1: Absorption (38 species) (Odum et al., 1997; Griffin et al., 1999) MADRID 2: Absorption & dissolution (42 VOCs, 5 hydrophobic and 5 hydrophilic surrogate SOA) (Pun et al., 2002)

5. CMAQ vs. CMAQ-MADRID: Chemical Mechanisms Models-3/CMAQ Gas-phase CBM-IV, RADM2, chemistry SAPRC-99 (1) Aqueous RADM chemistry (Walcek and Taylor, 1986) - 33 aqueous/ionic species - 18 equilibria - 5 kinetic reactions - 55 species for wet deposition Heterogeneous Not treated chemistry CMAQ-MADRID CBM-IV/RADM2 (MADRID 1) CACM (MADRID 2) CMU (Seinfeld and Pandis, 1998) - 55 aqueous/ionic species - 34 equilibria - 99 kinetic reactions - 88 species for wet deposition HO 2, NO 2, NO 3, N 2 O 5 on PM N 2 O 5 in droplet (Jacob, 2000) (1) available in July 2002 version of Models-3/CMAQ

6. Application of CMAQ-MADRID: SCAQS 1987 Episode Period 25-29 August 1987 Domain 63 x 28 grid cells Horizontal resolution 5 km Vertical resolution 15 layers Meteorology –MM5/FDDA –Nested grids (45, 15, 5 km) Emissions –NO x, SO 2, CO, SO 3, VOC (Allen and Wagner, 1992) –NH 3 and PM (Meng et al., 1998) –Adjustment in VOC (Pai et al., 2000) Initial and boundary conditions –Gases (Pai et al., 2000) –PM (San Nicholas Island)

7. SCAQS Modeling Domain and Ozone/PM Measurement Sites ▲ - sites with PM (5 samples/day) and ozone (hourly) measurements  - sites with ozone (hourly) measurements Pink/Red - sites with ozone time series plots Blue/Red - sites with 24-hr average PM concentrations/size distribution plots

8. Observed vs. Simulated Ozone Mixing Ratios

9. Observed vs. Simulated PM 2.5 Concentrations

10. MADRID 1 vs. MADRID 2 (Riverside) 28-August 27-August Observed MADRID 1 MADRID 2 Nitrate OC Sulfate EC Ammonium Other

11. Condensational Growth (Moving-Center vs. Finite-Difference)

12. Gas/Particle Mass Transfer (Hybrid vs. Bulk Equilibrium)

13. Gas/Particle Mass Transfer (CIT Bulk Equilibrium vs. CMU Hybrid) The CMU hybrid approach predicts more sodium nitrate in the coarse mode The CIT bulk equilibrium approach distributes most nitrate within the fine mode (PM 2.5 )

14. Model Performance for O 3 and PM 2.5

15. Summary of SCAQS Application CMAQ-MADRID provides a realistic representation of atmospheric PM. Secondary organic aerosol predictions are sensitive to different SOA formulations. Jacobson’s moving-center approach is the most accurate among the condensational growth algorithms tested. The CMU hybrid and the CIT bulk equilibrium approaches predict a realistic particle size distribution under most conditions. Heterogeneous chemistry increases H 2 O 2, HNO 3, and sulfate; decreases SO 2 and NO 2 ; affects O 3 and nitrate in both ways.

16. Acknowledgments EPRI: New aerosol & cloud modules CARB: MADRID2 aerosol module R. Griffin and D. Dabdub for providing source codes used in MADRID F. Binkowski and S. Leduc for discussions regarding EPA Models-3/CAMQ Project managers: N. Kumar (EPRI), A. Hansen (EPRI), N. Motallebi (CARB)