CALPUFF

CALPUFF is an advanced, integrated Lagrangian puff modeling system for the simulation of atmospheric pollution dispersion (Code of Federal Register, 40 CFD). The model has been adopted by the USEPA in its Guideline on Air Quality Models as a preferred model for assessing long‐range transport of pollutants and their impacts on Federal Class I areas and on a case‐by‐case basis for certain near‐field applications involving complex meteorological conditions (Scire et al. 1990; Turner 1994).

The integrated modeling system consists of three main components and a set of preprocessing and post‐processing programs. The main components of the modeling system are CALMET (a diagnostic three‐dimensional meteorological model), CALPUFF (an air quality dispersion model), and CALPOST (a post‐processing package). Each of these programs has a graphical user interface. In addition to these components, there are numerous other processors that may be used to prepare geophysical (land use and terrain) data in many standard formats, meteorological data (surface, upper air, precipitation, and buoy data), and interfaces to other models such as the Penn State/NCAR Mesoscale Model (MM5), the National Centers for Environmental Prediction Eta model, and the RAMS meteorological model.

The CALPUFF model is designed to simulate the dispersion of buoyant, puff, or continuous point and area pollution sources as well as the dispersion of buoyant, continuous line sources. The model also includes algorithms for handling the effect of downwash by nearby buildings in the path of the pollution plumes (Turner 1994).

More insights are given in Section D.5 on dispersion modeling and understanding how to predict the time‐averaged concentration of contaminants emitted into the atmosphere from a single elevated source or complicated industrial complexes with multiple emission points.

Attainment and Non‐Attainment Areas

States are divided into air quality control regions (AQRs). An AQR that has air quality equal to or better than the primary standard listed in NAAQS is called an attainment area. And those areas that do not meet the primary standard are called non‐attainment areas. Figure 4.14 shows all non‐attainment counties in the United States, including Alaska and Guam for six NAAQS pollutants.