The Pktreduc program reduces the size of growth packets (using the /PROJECTION/ packet in the GCNTL file), but keeps the same information. This is done by identifying and implementing state defaults where possible. This program works solely with growth packets that have state/county and SCC entries only; it will not work if the packet contains SIC, MACT, or pollutant codes.

The program identifies the most common growth factor for each state across the many counties for each SCC, and this factor is assigned as the default for the state/SCC combinations. The county/SCC-specific entries are left as is. In this way, the contents of the file are the same as far as SMOKE is concerned, but the file processes through Cntlmat much faster because the growth packet is much smaller. It is acceptable if state defaults are already in the file, and Pktreduc will leave these untouched. When state defaults are found for a state (i.e., county code is set to 000), the program skips reductions for that state and no changes are made (even if they could be).