The present study proposes a steady-state mathematical model for dispersion of contaminants in low winds that takes into account the along-wind diffusion, but it does not consider the variable wind direction typical of low wind. The solution of the advection–diffusion equation for these conditions is obtained applying the generalized integral Laplace transform technique (GILTT) method and the eddy diffusivities are functions of distance from the source. The performance of the model was evaluated against the field experiments at the Idaho National Engineering Laboratory, the Lilleström dataset and during convective conditions at the Indian Institute of Technology.