This study,developed an improved model for the dispersion of released toxic gases, SLABi, based on the widely used model SLAB. Two major improvements enhanced the model's ability to represent observations. First, SLAB was upgraded to account for temporal variation in wind vectors. Thus, real-time changes in meteorological conditions can be considered in dispersion forecasting. Second, a source term module was developed and embedded in SLABi to standardize the procedure of emission calculation. Both the standard SLAB model and the SLABi model were applied to a case study to evaluate the impact of time-varying winds on the dispersion of released gases. The results showed that Meteorology has a significant influence on the dispersion of released gases. The SLABi model can provide decision makers with timely and accurate guidance, so as to minimize hazards to people and the environment. (C) 2015 Elsevier Ltd. All rights reserved.