CMAQv5.0.2 Aqueous chemistry

Brief Description

Rate constant for the metal catalysis pathway for SO2 oxidation (aqueous-phase) was updated in CMAQv5.0 following Martin and Goodman (1991). Alexander et al. (2009) implemented the metal catalysis pathway of Martin and Goodman (1991) into the GEOS-Chem model which did not include the sulfate inhibition effect. The procedure used by Alexander et al. (2009) was followed for implmenting the metal catalysis pathway into CMAQv5.0. The Electric Power Research Institute stated that Martin and Goodman (1991) includes sulfate inbihition effect and suggested that it be implemented into CMAQ. Sulfate inhibition effect is now implemented into CMAQv5.0.2 following Martin and Good (1991).

Significance and Impact

The sulfate inhibition reduces sulfate production in winter but not in summer.

Affected files

aqchem.F

References

Martin, R. L. and T.W. Good (1991), Catalyzed oxidation of sulfur dioxide in solution: the iron-manganese synercism, Atmospheric Environment, 25A, 2395-2399. Alexander, B., R.J. Park, D.J. Jacob, S. Gong (2009), Transition metal-catalyzed oxidation of atmospheric sulfur: global implications for the sulfur budget, JGR, 114, D02309.

Contact

Golam Sarwar, Atmospheric Modeling and Analysis Division, U.S. EPA