A novel method to simulate the wind and turbulence around obstacles, such as buildings, has been developed for use in a computer model that was previously used only to study turbulence and clouds over flat Earth surface. The method, called the Quasi-Solid Box Method, forces the simulated flow to stop in the model grid-cells that are inside an obstacle. The accuracy of the method is tested using cases of a flow past an idealized single rectangular building, a cubic building rotated by 45^o, and a building in the form of a cylinder. The simulations are compared with wind tunnel observations around a small model building and to results from other models. The modeled gas tracer dispersion around the building also agrees quite well observations. We also report results for successful simulation of a flow around a cubic building rotated by 45^o relative to the flow, and around a building in the form of a cylinder of aspect ratio of one. The main appeal of the new method is its simplicity that requires very minor modifications to the model code. The improved model can be used for detailed studies of the impact of climate change on urban environments.