Wind speed determines the amount of initial dilution experienced by a plume. The wind speed is used in:

• The denominator of the steady-state Gaussian dispersion equation

• Calculation of plume rise associated with point source releases,

• Estimation of aerodynamic effects in downwash calculations, and,

• Determination of atmospheric stability in conjunction with other variables.

  

Typically, "Cup Anemometer" or "Propeller Anemometer" (mechanical sensor) is used for in situ monitoring of wind speed. The rotating cup anemometer consists of three, four, and sometimes six hemispherical or cone-shaped cups mounted symmetrically about a vertical axis of rotation. The three cup anemometer is recommended; this design has been shown to exert a more uniform torque throughout a revolution.