This document discusses different types of plumes that can occur from smokestacks and their characteristics. It describes looping plumes as occurring in highly unstable super adiabatic environments, causing pollutants to mix both up and down rapidly and concentrate near the ground. Neutral plumes rise vertically until the air densities equalize. Coning plumes form when winds exceed 32km/hr or cloud cover blocks radiation, taking a cone shape. Fanning plumes occur under inversion conditions, causing horizontal rather than upward plume movement. Lofting plumes have strong upward mixing above the stack but downward mixing is blocked by inversion, rapidly dispersing pollutants away from the ground.

1. NAME – SANJIB KUNDU
ROLL – 27101320017
REGISTRATION – 202710101320052
REGISTRATION – 202710101320052
TRADE – CIVIL ( b.tech )
YEAR – 4th ( 7th semester )
SUBJECT – Air and Noise Pollution and Control
CE(PE)703A

2.  Looping Plume
 Looping plume is of wavy character and occurs in super adiabatic environment
(ELR>ALR), which produces highly unstable atmosphere because of rapid mixing.
 In an unstable atmosphere, rapid air movements take place vertically both upward and
downward and the plume becomes a looping plume.
 As a result of this, high concentrations of pollutants may occur near the ground. To
disperse these pollutants, it is advisable to design high stack where atmosphere is
generally super adiabatic

3. Neutral Plume
 Neutral plume occurs in neutral atmospheric conditions (ELR=ALR).Such type
of plume rises vertically in an upward direction.
 The upward lifting of the plume will continue till it reaches a height where
density and temperature of surrounding air are equal to it.

4.  Coning Plume
 It is calculated that when horizontal wind velocity exceeds 32km/hour and
under the condition of cloud blocking solar radiations at day time and
terrestrial radiation at night, neutral plume tends to form cone like structure
known as coning plume.
 Under sub-adiabatic conditions (ELR < ALR), when there is limited vertical
mixing and environment is slightly stable, the plume also attains cone like
structure and is coning plume.
structure and is coning plume.

5.  Fanning Plume
 Under extreme inversion condition (due to negative lapse rate), fanning plume
is obtained. Under condition of inversion, stable environmental condition
exists just above the stack and plume does not move upwardly but horizontally.
 Occurs generally in less turbulence condition.

6.  Lofting Plume
 Under conditions of strong super adiabatic lapse rate just above the stack and negative
lapse rate (inversion) just below the opening of stack, lofting plume is obtained
 The upward mixing of plume is very rapid and turbulent, but downward mixing is less
because the downward movement is prevented by inversion.
 The dispersion of pollutants therefore becomes rapid and pollutants cannot come down
to the ground. Such kind of a plume is ideal for dispersion of air pollutants and
protection of living beings to a great extent