One sentence to introduce this project: A Gaussian multi-puff gas dipersion model using PyCUDA/CUDA to accelerate the computation. About the performance: The model was developed against with GTX570/CUDA 4.0/Fedora 13, but also tested under GTS250/CUDA3.0/Windows 7. It showed huge acceleration comparing with Intel i7 workstation. The computation would comsume about 30 seconds to compute a middle-size accident as default configuration in source codes. License: ALL FILES ARE LICENSED UNDER GPLv3. No statements were put in the source code files. But there are NO exceptions. Some packages used in this project have their own licenses. These licenses should be followed.