Atmospheric Modeling and Analysis Research
CMAQ Aerosol Module
Atmospheric particulate matter (PM) is linked with acute and chronic health effects, visibility degradation, acid and nutrient deposition, and climate change. Accurate predictions of the PM mass concentration, composition, and size distribution are necessary for assessing the potential impacts of future air quality regulations and future climate on these health and environmental outcomes. The objective of this research is to improve predictions of PM by advancing the scientific algorithms, computational efficiency, and numerical stability of the CMAQ aerosol module.
CMAQ version 5.0 includes a complete redesign of the aerosol module eliminating unnecessary dependencies and duplications across modules. PM is now speciated into 9 additional components including trace metals and non-carbon organic mass, and a new scheme predicts the oxidative aging of primary organic carbon. The additional speciation allows for a greater interaction of windblown dust and seasalt with inorganic species such as sulfate and nitrate. For example, the explicit treatment of iron and manganese allows for a more detailed treatment of S(IV) to S(VI) conversion in aqueous chemistry routines. CMAQ 5.0 also uses ISORROPIA II, which includes calcium, potassium, and magnesium, for equilibrium and dynamic mass transfer of inorganic species between the gas and aerosol phase.
The two-way coupling of WRF and CMAQ enables interaction between aerosols and meteorology and will support future investigations of the influence of climate change on air quality. In CMAQ 5.0, aerosol information is used for optical properties in WRF’s radiation calculations thus enabling an examination of the direct effect of aerosols. Future work will more tightly couple aerosol information from CMAQ with WRF to allow for determination of the indirect effect as well as cloud droplet resolved chemistry.
- Carlton, A. G., P. V. Bhave, S. L. Napelenok, E. D. Edney, G. Sarwar, R. W. Pinder, G. A. Pouliot, and M. Houyoux (2010), Model representation of secondary organic aerosol in CMAQv4.7, Environ. Sci. Technol., 44(22), 8553-8560.
- Foley, K. M., et al. (2010), Incremental testing of the Community Multiscale Air Quality (CMAQ) modeling system version 4.7, Geosci. Model Dev., 3(1), 205-226.
- Kelly,; J. T., P. V. Bhave, C. G. Nolte, U. Shankar, and K. M . Foley (2010), Simulating emission and chemical evolution of coarse sea-salt particles in the Community Multiscale Air Quality (CMAQ) model, Geosci. Model Dev., 3, 257-273.
- Pye, H. O. T. and G. A. Pouliot (2012), Modeling the role of alkanes, polycyclic aromatic hydrocarbons, and their oligomers in secondary organic aerosol formation, submitted to Environ. Sci. Technol.
- Reff, A., P. V. Bhave, H. Simon, T. G. Pace, G. A. Pouliot, J. D. Mobley, and M. Houyoux (2009), Emissions inventory of PM2.5 trace elements across the United States, Environ. Sci. Technol., 43(15), 5790-5796.
- Simon, H., and P. V. Bhave (2012), Simulating the degree of oxidation in atmospheric organic particles, Environ. Sci. Technol., 46(1), 331-339.