1. Evaluation of Models-3 CMAQ Annual Simulation Brian Eder, Shaocai Yu, Robin Dennis, Alice Gilliland, Steve Howard, Alfreida Rankin Atmospheric Modeling Division National Exposure Research Laboratory U.S. Environmental Protection Agency Atmospheric Sciences Modeling Division Air Resources Laboratory National Oceanic and Atmospheric Administration Research Triangle Park, NC

2. CMAQ General Description
CMAQ is an Eulerian model that simulates the atmospheric and surface processes affecting the transport, transformation and deposition of air pollutants and their precursors.
CMAQ employs a “one atmosphere” philosophy that tackles the complex interactions among multiple atmospheric pollutants on a myriad of scales.
Pollutants considered within CMAQ include tropospheric ozone, particulate matter, airborne toxics, as well as acidic and nutrient species. The model also calculates visibility parameters.

3. CMAQ Evaluation CMAQ needs to be evaluated against observational data:
- characterize its performance
- establish confidence in the regulatory community
Evaluation compares simulated ambient concentrations using:
- IMPROVE
- CASTNet
- STN
Unfortunately, these networks have different sampling protocols:
- temporal issues: weekly vs. daily
- spatial issues: remote, rural, urban
- measurement issues: filters, flow rates

4. Species: SO4, NO3, NH4, PM2.5, OC, EC (μg m-3)
Statistics: Summary statistics and plots
Mean Bias (MB)
Normalized Mean Bias (NMB)
Root Mean Square Error (RMSE)
Normalized Mean Error (NME)
Observational Data:
- IMPROVE (111 sites)
CASTNet (73 sites)
STN (varied)

5. SO4 – Annual Results NMB NME CASTNet IMPROVE STN n 3,737 13,447 6,970
0.92
0.86
0.78 MB
-0.12
0.04
0.22
NMB(%)
-4.0
2.0
6.0
RMSE
1.12
1.29
2.32
NME(%)
24.0
40.0
43.0
NME