For existing smokestacks, it is usually not economically feasible to rebuild the smokestack taller. Or, there are aesthetic and community considerations that prevent the construction of a tall smokestack. Instead, there are things that can be done to raise the effective stack height, which are methods to make the smoke go higher after it leaves the stack. One way is to increase the temperature of the smoke leaving the smokestack.

The higher the exit temperature, the greater the positive buoyancy in smoke streaming out of the smokestack. The smoke has to rise higher before it has adiabatically cooled to the same temperature as the surrounding air (and thus reaching a state of neutral buoyancy).