Community Multiscale Air Quality Model (CMAQ)

1. Community Multiscale Air Quality Model (CMAQ) Gail Tonnesen, Zion Wang UCR Regional Modeling Center Training January 16, 2002

2. History • The development of comprehensive air quality models started in the late seventies. • Eulerian models developed are used to address ozone and acid deposition issues and applied under relatively prescriptive implementation guidance strategies. • flexibility to deal with other issues, such as particulate matter or toxics, was very limited. University of California at Riverside, Regional Modeling Center (RMC)

3. History • In the Clean Air Act Amendments of 1990 (CAAA-90), a wide range of additional issues were identified including • visibility, • fine and coarse particles, • indirect exposure to toxic pollutants such as heavy metals, • semi-volatile organic species, and • nutrient deposition to water bodies. University of California at Riverside, Regional Modeling Center (RMC)

4. CMAQ – Goal • CMAQ is a “one atmosphere” model to simulate • Ozone, • PM, • Haze, • Acid deposition, and • Nutrient and toxic deposition. University of California at Riverside, Regional Modeling Center (RMC)

5. Development of CMAQ • The Community Multiscale Air Quality Model (CMAQ) is developed to process great and diverse information from • complicated emissions mixtures and complex distributions of sources, to • modeling the complexities of atmospheric processes that transport and transform these mixtures in a dynamic environment, • operates on a large range of time scales covering minutes to days and weeks, and University of California at Riverside, Regional Modeling Center (RMC)

6. Development of CMAQ • corresponding spatial scales are commensurately large, ranging from local to continental scales. • meeting NAAQS requirements and other goals for a cleaner environment varying over a range of time scales, from peak hourly to annual averages. University of California at Riverside, Regional Modeling Center (RMC)

7. CMAQ – Recap • The Community Multiscale Air Quality Model: • addresses air quality from this “one atmosphere” multi-pollutant perspective, • A multi-pollutant, multi-scale air quality model, • Capable of simulating all atmospheric and land processes that affect the transport, transformation, and deposition of atmospheric pollutants and/or their precursors on both regional and urban scales. • It is designed as a science-based modeling tool for handling all the major pollutant issues (including photochemical oxidants, particulate matter, acidic, and nutrient deposition) holistically University of California at Riverside, Regional Modeling Center (RMC)

8. SMOKE CMAQ Modeling Systems University of California at Riverside, Regional Modeling Center (RMC)

9. SMOKE CMAQ Science Processors University of California at Riverside, Regional Modeling Center (RMC)

10. CMAQ Chemical Transport Model (CCTM) • The CCTM simulates the relevant and major atmospheric chemistry, transport and deposition processes involved throughout the modeling domains: • Advection and diffusion • Gas phase chemistry • Plume-in-Grid (PinG) • Particle modeling and visibility • Cloud process • Photolysis rates University of California at Riverside, Regional Modeling Center (RMC)