Central Campus Air Quality Model (CCAQM) Instructions
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Run Conditions
o Wind
Speed
(m/s) - The minimum choice available for CALINE4 (0.5 m/s).
Alternatively, EPA (1992) recommends a value of 1 m/s as the
worst-case wind speed.
o Wind
Direction
(degrees) - should be specified with respect to the chosen Cartesian
coordinate system, with zero degrees corresponding to true north.
This is the direction the wind is blowing from, measured clockwise
in degrees from the north (0 = north, 90 = east, 180 = south, 270 =
west). Most users should opt for the "Worst-Case Wind Angle" choice
on the Job Parameters screen. If "Worst-Case" is selected, CALINE4
does not use this input.
o Wind
Direction Std. Dev.
(degrees) - The statistical standard deviation of the Wind
Direction. See Table 5 for recommended values.
o Atmospheric
Stability Class
(1-7) - A measure of the turbulence of the atmosphere. Values 1
through 7 correspond to the standard definitions for stability class
A through E. Stability class G (or 7) represents the most stable
conditions. See Table for recommendations of worst-case conditions.
o Mixing
Height
(m) - The altitude to which thermal turbulence occurs due to solar
heating of the ground. Reasonable values for the worst-case mixing
height rarely have a significant impact on CALINE4 model results.
o Ambient
Temperature
(degrees C) - The ambient air temperature significantly affects
vehicle CO emissions. A temperature that reflects wintertime
conditions should be selected, expressed in degrees Celsius.
o Ambient
Pollution Concentration
(ppm) - This measure reflects the pre-existing background level of
carbon monoxide, expressed in parts per million. CALINE4 adds the
pre-existing and modeled CO concentrations together to determine the
total impact at each receptor. A reasonable ambient concentration
of CO is 3 ppm. |