CALPUFF is an advanced, integrated Gaussian puff modeling system for the simulation of air pollution dispersion. The model has been adopted by the U.S. Environmental Protection Agency (U.S. EPA) in its Guideline on Air Quality Models as a preferred model for assessing the long range transport of air pollutants and their impacts on national parks, wilderness areas and other Federal lands (known as Federal Class I areas) as well as on a case-by-case basis for certain near-field applications involving complex meteorological conditions.