airborne releases from area sources -Reply

[Charles Willis <CAW@nrc.gov>]

William,

Several approaches are used but the "virtual point source" approach may be most
understandable.  Start with the concentration per unit release, at the area source
(before further dilution)  and calculate the (virtual) distance from a point source to
give the same concentration.  To calculate the concentration at a point downwind
from your area source, add the calculated "virtual" distance to the real distance. 
When the virtual distance is small compared to the actual distance, the virtual
distance can be ignored.

Charlie Willis
caw@nrc.gov
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