Central Campus Air Quality Model (CCAQM) Instructions
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Job Parameters
o Run
Type
- Different choices determine averaging times (for CO
concentrations) and how the hourly average wind angle(s) will be
determined. (Wind angle is the angle between the roadway link and
the wind direction. CALINE4 calculates the angles based on data in
the Link Geometry and Run Conditions Screens.) Most users should
invoke the "worst-case wind angle" run type and apply a persistence
factor of 0.6 to 0.7 in order to estimate an 8-hour average CO
concentration.
§ Standard
- Calculates 1-hour average CO concentrations at the receptors. The
user must input a wind direction on the Run Conditions Screen.
§ Multi-Run
- Calculates 8-hour average CO concentrations at the receptors. The
user must input wind angles for each hour.
§
Worst-case wind angle - Calculates 1-hour average CO concentrations
at the receptors. The model selects the wind angles that produce
the highest CO concentrations at each of the receptors. This is the
most appropriate choice for most users.
§
Multi-Run/Worst-Case hybrid - Calculates 8-hour average CO
concentrations at the receptors. The model selects the wind angles
that produce the highest CO concentrations at each of the receptors.
o Aerodynamic
Roughness Coefficient
- These choices determine the amount of local air turbulence that
affects plume spreading. CL4 offers the following 4 choices for
aerodynamic roughness coefficient:
§
Rural:
Roughness Coefficient = 10 cm
§
Suburban: Roughness Coefficient = 100 cm
§
Central
Business District: Roughness Coefficient = 400 cm
§
Other
o Model
Information
- Provides summary information for convenience and quality
assurance.
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