Characteristic scaling parameters in the planetary boundary layer have been applied to estimate the dispersion of nonbuoyant gaseous pollutants. Vertical and lateral spread are treated separately, and the choice of parameters for the dispersion models depends upon the actual state of the planetary boundary layer. The lateral concentration distribution at the surface was usually found to be a Gaussian distribution. The vertical concentration distribution was more often other than Gaussian. For the different scaling regions of the atmosphere, methods are proposed for estimating the crosswind integrated concentrations, as functions of distance from the source, and are compared using results from tracer experiments. The proposed methods estimate the transport and dispersion directly from the turbulent state of the atmosphere. In all the scaling regions, the various methods adequately estimated the observed concentrations. The turbulence, and thus the dispersion, is better explained and modeled in the surface layer of the atmosphere (stable and unstable), than within the layers above the surface layer. Some success was demonstrated for releases in the stable local scaling (z-less) layer, and in the mixed layer and the near-neutral layer.