The aim of this study is to compare the CALPUFF and LAMBDA models and evaluate the regulatory model CALPUFF accuracy in situations of line instant source emissions. Line source emissions exist in a variety of situations in the environmental field. Paved and unpaved roads are the most common examples of line sources. For instance, in the mining sector these two types of sources play an important role of anthropogenic influences in the environment. The OLAD experiment is appropriate to evaluate these models and check the accuracy of both. The CALPUFF results show in the simulations for short and long distances a systematic tendency of sub-prediction for the concentration. The LAMBDA model presented better accuracy in the prediction of natural pollutant dispersion even disregarding the spatial variability of meteorological field and topography. When the LAMBDA model is used the flow of pollutants to greater distances is less pronounced, especially because of the time step of one second adopted in the simulation.
