In Section 2.9.1, “Check the correctness and consistency of input file formats”, we explained that Smkinven ensures that the input files are correct and that the same format is used. In addition, Smkinven checks for duplicate records across the entire set of inventory input files. A duplicate record is one that has the same source characteristics (defined in Section 2.8.1, “Summary of SMOKE processing categories”) and pollutants as another record in the inventory. Smkinven provides an option that allows you to instruct Smkinven whether duplicates should cause a warning message or an error. In some cases, you may not expect duplicates in your inventory, in which case you can have Smkinven abort after reporting all duplicates. In other cases, you can instruct Smkinven to sum the emissions across all duplicate records. See Section 6.13, “Smkinven” for more information on the different approaches.