This report is part of a project to characterize cotton gin emissions from the standpoint of stack sampling. The impetus behind this project was the urgent need to collect additional cotton gin emissions data to address current regulatory issues. A key component of this study was focused on Environmental Protection Agency (EPA) total particulate emission factors. There is no total particulate emission factor published for mote cyclone robber systems in the 1996 EPA AP-42. The objective of this study was to collect total particulate emission factor data for mote cyclone robber cleaning systems from cotton gins located in regions across the cotton belt using EPA-approved stack sampling methodology. The project plan included sampling seven cotton gins. Key factors for selecting specific cotton gins included: 1) facility location, 2) production capacity, 3) processing systems and 4) abatement technologies. Three gins with mote cyclone robber systems were sampled. The average production rate during testing for the three gins was 25.6 bales/h. The average mote cyclone robber system total particulate emission factor based on three tests (nine total test runs) was 0.050 kg/227-kg bale (0.111 lb/500-lb bale). The mote cyclone robber systems emission rate test averages ranged from 0.66 to 2.15 kg/h (1.46-4.74 lb/h).