This chapter includes a general characterization of the atmospheric boundary layer with an analysis of micro, macro, and synoptic atmospheric scales in the troposphere. The dimensional scales and frequencies of average flow, turbulence and atmospheric waves are discussed in relation with the transport of scalar and vector variables. The atmospheric stability and instability conditions associated with the vertical adiabatic gradient of actual and potential temperatures with daily variation of the atmospheric boundary layer were evaluated. The dynamics of atmospheric boundary layers, top inversionTop inversion, mixed layerMixed layer, and surface layers, along with subsidence and divergency, play a significant role as discussed.