An analytical model for the crosswind integrated concentrations released from a source in an inversion layer is formulated by considering the wind speed as a linear profile of vertical height and eddy diffusivity as a power law profile of vertical height, the separation of variables technique is used to solve the advection –diffusion equation. The analytical model is compared with data collected from nine experiments conducted at Inshas, Cairo (Egypt). The model shows a good agreement between observed and calculated concentration.