CEMScan reads a year’s worth of CEM data and calculates summed annual NOx emissions, SO₂ emissions, heat input, gross load, and steam load for each uniquie ORIS/boiler combination in the output CEM data. While writing the output, CEMScan will skip any ORIS/boiler combinations where the total annual NOx emissions are zero or null or where the total annual gross load, steam load, and heat input are zero or null. The program will write these ORIS/boiler combinations to the report file along with a flag indicating that the combination was not written to the output file. The output from CEMScan is used by Smkinven to calculate hourly emissions from annual inventory data when reading CEM data. Detail information is described in Section 2.9.19, “Processing hour-specific CEM data”.