#
Central Campus Air Quality Model (CCAQM) Instructions
**Gaussian
Model Coordinate System**
The location
of the source is important in determining the pollution
concentration at a receptor. Pollutants from a smoke stack are
assumed to spread according to the figure below. Emissions
from vehicles traveling along a road will behave similarly, except
the height of the source is located at ground level, and the stack
can be thought of as extended in the y-direction according the
length of the road. Thus, the location of the source relative
to the location of the chosen receptors will partially determine the
pollution concentration at those receptors. The pollution
concentration is also dependent on emission rate, stability class,
wind direction, and wind speed.
In this
orientation, the positive x-direction is downwind, and x is the
distance downwind. The positive y-direction is normal to the
x-direction so that y is the lateral distance from the plume
centerline. The z-direction indicates the elevation of the
pollutant; therefore, the z distance is the vertical distance to the
centerline of the plume.
Coordinate System for Gaussian Model |