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DFE World: Design & the Global Environment
Photograph of Nature
Air Pollution

Atmospheric Stability
Dispersion Coefficients
Coordinate System
Central Campus Map
Model Output


Central Campus Air Quality Model (CCAQM) Instructions


Line Sources

Line source models are a way to represent a steady stream of vehicles traveling along a road.  The line source model used in this tutorial is a Gaussian distribution, which is a statistical representation of the dispersion of emissions from the road in a given space.






Model Inputs
The Gaussian distribution of a line source is given by the following equation:



  • C(x) = concentration at ground level at point (x,y) in units g/m3

  • q = emission rate per distance, g/mile

  • u = wind speed, m/s

  • σz = vertical dispersion coefficient, m