Modeling Tip – June 2012

CALPUFF model runs can take an extremely long time to complete, but there may be times when sources have been divided into multiple runs. In order to estimate the total impact of all sources, the CALSUM utility can be used to create a single data file which contains the cumulative impacts. CALSUM can support the following output data types:

• CONC.DAT (concentration)


• DFLX.DAT (dry deposition fluxes)


• WFLX.DAT (wet deposition fluxes)

The latest release of CALPUFF View includes the CALSUM Wizard which steps users through the process of running CALSUM.

Note that CALSUM can only be used if:

1. The output files are of the same type (containing either concentrations, wet deposition fluxes, or dry deposition fluxes)


2. The time periods contained in the files are identical


3. The species are the same and in the same order


4. The receptors (e.g., sampling, discrete, etc.) are the same, in terms of number, location, and order

Once that information has been verified, follow these steps to run the CALSUM Wizard:

Step 1: Begin by exporting the sources from each project whose output will be combined. Use the Export | Sources menu option to save the sources to an Excel spreadsheet.

Step 2:Create a new project to store the combined results. Since the parameters from each run must be the identical, select the Save Project As option with one of your CALPUFF View projects open.

Step 3:Select the Import | Sources menu option and import the Excel spreadsheets you exported in Step 1. Your new project will now contain all of the sources whose output will be combined in CALSUM.

Step 4:Select Tools | CALSUM Wizard. On the first step, provide an optional title for the run. The input, list, and output files will be automatically created, but you can change the names of any files as desired. Click the Next button when ready.

Step 5:Verify the Species list. Recall that the species must be the same and in the same order for all projects to be combined. You can import a Species List using the Import button. Click Next to proceed.

You have to specify which output files will be combined in the Data Files and Scaling Options. Select the Add File button to identify each output file.

Step 6:The concentrations or deposition fluxes in each file may be scaled by using a linear operator of the form (Ax+B) where:

x represents either the concentration or deposition flux
A is the multiplicative constant (A-scale)
B is the additive constant

For example, you can use the B-Scale to add a constant background concentration to the model results. Enable the Scaling Factor checkbox for any specified output file to add scaling factors.

Step 7:After specifying all of the CALSUM parameters, press the Run button to run CALSUM. Click OK to close the CALSUM Wizard when the run is complete.

Step 8:Verify your CALPOST model options. When the options are set, select Run | CALPOST Model to process the combined concentrations or deposition fluxes.