Alternative Methods for Determining Dispersion Coefficients

 

DOWNWIND GROUND-LEVEL CONCENTRATIONS

Concentrations directly downwind of are of greatest interest because these are the highest ground level concentrations experienced.

Thus with y=0 the model simplifies even further to:

EMMISSIONS FROM GROUND LEVEL SOURCES

If we have a situation such as cool vapour escaping from an open drum, where there is plume rise (because the vapour is not buoyant) we can simplify even further since H=0
Or to look at horizontal spread to find the area over which a spillage might have an effect we could use.
 

Task 6:

A pool of solvent standing on the ground is evaporating at a rate of 50000 µg/s.
The wind speed is 2m/s and the sky is totally overcast.

By use of a spreadsheet estimate the distance downwind at which the solvent will not be detectable using an analyser with a limit of detection of 50 µg/m3.

It is suggested that an interval of 0.03km be used when calculating data.