A methodology is proposed for modeling the diffusion of fragrances released from a moving source. First, we started with a one-dimensional model considering molecular diffusion of -pinene in air as the only mass transport mechanism. The validation was performed in a diffusion tube, and a system was developed to move the scented source along the axial direction. Results showed that experimental data fitted well with the numerical simulation, suggesting this model as a valid tool to describe the trail of a fragrance released from a moving source for low Re of the order of 10. In the case of a person walking at the speed of 1.34 m/s in a room or corridor inside a building, three-dimensional models are required and mass transport of the perfume to the surrounding air will be dominated by turbulent diffusion or eddy diffusion D-t which is two orders of magnitude higher than molecular diffusion. (c) 2018 American Institute of Chemical Engineers AIChE J, 64: 2890-2897, 2018