Plumes:- Behavior of gases emitted from Stack depends upon the prevailing Environmental Conditions. Different types of plume behavior for various atmospheric stability conditions.
(1) Looping Plume: Plume is formed when the environmental lapse rate becomes more than the Dry Adiabatic Lapse Rate i.e. occurs in a super adiabatic environment. In an unstable Atmosphere, rapid air moments take place vertically both upward and downward And the plume becomes Looping Plume.
(2) Coning plume: Environmental lapse rate becomes slightly less than the Dry Adiabatic Lapse i.e under Sub Adiabatic Lapse rate. Under sub adiabatic condition When there is a limited vertical mixture and the environment is slightly stable the plume also attains a cone-like structure and conical plume.
(3) Fanning plume: Under extreme inversion condition Fanning plume is obtained. environmental lapse rate becomes less than the Dry Adiabatic Lapse i.e under Sub Adiabatic Lapse rate. The environment is highly stable (Invasion occurs).
(4) Lofting plume: It is a Highly unstable atmosphere because of rapid mixing. In an unstable atmosphere super adiabatic lies above sub adiabatic environment downward motion is prevented by inversion but upward mixing occurred.
(5) Fulminating plume: Just reverse of Lofting condition when inversion lies above super adiabatic environment. Pollutants cannot move above the top of the stack because of inversion.
(6) Trapping plume: Condition occurred when super adiabatic lies between two inversion layers, Such types of plume is therefore, teemed and trapping plume.
(7) Neutral Plume:- it occurs in a neutral atmosphere condition such types of plumes rises vertically in an upward distraction environmental lapse rate becomes equal to Dry Adiabatic Lapse Rate.