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Incorporation of the MADRID Model into CMAQ for Aerosol Dynamics and Mass Transfer Simulation

This article discusses the incorporation of the MADRID model into the CMAQ model for simulating aerosol dynamics, reaction, ionization, and dissolution. The model includes processes such as gas/particle mass transfer, nucleation, condensation, coagulation, and absorption. The study also presents the application of the model in two case studies: the SCAQS episode in Los Angeles and the SOS episode in Nashville.

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Incorporation of the MADRID Model into CMAQ for Aerosol Dynamics and Mass Transfer Simulation

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  1. Incorporation of the Model of Aerosol Dynamics, Reaction, Ionization and Dissolution (MADRID) into CMAQ Yang Zhang, Betty K. Pun, Krish Vijayaraghavan, Shiang-Yuh Wu and Christian Seigneur AER, San Ramon, CA CMAQ Workshop, October 2002

  2. MADRIDModel of Aerosol Dynamics, Reaction, Ionization, and Dissolution Gas/particle mass transfer • Hybrid algorithm • Full equilibrium algorithm Coagulation not important under polluted conditions Nucleation Condensable gases Condensation Existing Particles Coagulation

  3. Gas-to-Particle Conversion Processes in MADRID • Nucleation (McMurry and Friedlander,1979) • Thermodynamic equilibrium for inorganic species • ISORROPIA (SO4=, NO3-, NH4+, Na+, Cl-, water) • Equilibrium for organic species • Absorption based on empirical data • Dissolution and absorption from first principles • Diffusion-limited condensation/volatilization • Hybrid mass transfer from Calpado & Pandis or from Meng et al. • Moving-center algorithm of Jacobson

  4. CMAQ Modal size distribution NH4+, SO4=, NO3-,Na+, Cl- Coagulation Nucleation Full equilibrium approach to simulate mass transfer Standard dry deposition Absorption (irreversible) of 6 SOA using chamber data MADRID Sectional representation Same species Not treated New particle formation Hybrid or full equilibrium approach Revised flux approach Two SOA modules available Major Differences between MADRID and Original CMAQ Module

  5. MADRID 1 Modified CBM-IV & RADM2 4 anthropogenic SOA (aromatics) 34 biogenic SOA (monoterpenes) Absorption based on smog chamber data (Odum et al., 1997; Griffin et al., 1999) MADRID 2 CACM(1) 42 condensable products hydrophobic surrogate SOA 4 anthropogenic, 1 biogenic hydrophilic surrogate SOA 3 anthropogenic, 2 biogenic Absorption based on estimated properties Dissolution into existing aqueous particles SOA Modules in MADRID (1) Caltech atmospheric chemistry mechanism

  6. Meteorology Emissions, initial conditions, boundary conditions (modal) Conversion from modal to sectional Pre- Processors Sectional Modal Sectional Modal Sectional PM module CBM-IV / RADM2 + 19 biogenic reactions or CACM Modal PM module Gas-phase: CBM- IV + 3 biogenic reactions Chemical Transport Model Dry Deposition (sectional Vdep) Dry Deposition (modal Vdep) PM concentrations PM concentrations Sectional Modal Output PM chemical concentrations by size section PM deposition flux by chemical PM chemical concentrations by mode Incorporation of MADRID into Models-3

  7. Los Angeles Application • SCAQS episode of 27-28 August 1987 • Simulation using MM5 and CMAQ-MADRID 1

  8. SCAQS 1987 Episode • 25-29 August 1987 • Domain: 63 x 28 grid cells, consistent with previous modeling exercises • Grid Resolution: 5 km • MM5 used to generate input meteorology • Emission inventory developed from previous simulations

  9. SCAQS Modeling Domain CELA RIVR HAWT

  10. Model Performance Ozone and PM2.5 Species Error Bias O3 34% 9% PM2.5 44% 14%

  11. Model Performance PM2.5 Components Species Error Bias Sulfate 38% 11% Nitrate 45% -38% EC 54% -20% OC 49% -22%

  12. Sulfate Nitrate Ammonium EC OC Others Observed and Simulated PM2.5 Composition 27 August 28 August Observations MADRID 1

  13. Nashville, Tennessee Application • SOS episode of 15-18 July 1995 • Simulation using MM5 and CMAQ-MADRID 2

  14. Model Performance Ozone, PM2.5 and Sulfate Species Error Bias O3 17% 4% PM2.5 17% -15% Sulfate 13% -11%

  15. Formation of Condensable Organics Condensable products in Nashville Concentrations (mg/m3) Time (hour)

  16. Formation of Particulate Organics Nashville SOA (mg/m3) Time (hour)

  17. Hydrophobic vs. Hydrophilic Organics Nashville SOA (mg/m3) Time (hour)

  18. Sensitivity of Hydrophilic Organics to Henry’s Law Constant Nashville RH Hydrophilic SOA (mg/m3) RH Time (hour) Base case; H = 1.6 x 106 M/atm Sensitivity case; H = 109 M/atm

  19. Other Applications of MADRID • Nashville • comparison of three SOA modules • BRAVO • regional simulation with RADM2 and MADRID 1 • Southeast • applications of MADRID 1 and MADRID 2 • Eastern United States • application of MADRID 1 for one year for nitrogen deposition

  20. Lessons from PM Simulations • Accurate PM emission inventories are critical • Secondary organic aerosols remain a major source of uncertainty • Boundary conditions can have significant effects on O3 and PM predictions • Effects of clouds on sulfate need to be simulated for regional haze • Models yet to be tested for wintertime conditions

  21. Acknowledgments • Funding for this work was provided by EPRI and CARB • We would like to thank • J.H. Seinfeld, S. Pandis, M. Jacobson, R. Griffin, and A. Nenes for providing source codes used in MADRID • S. Leduc and F. Binkowski for discussions regarding CMAQ

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