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 1st stage mote systems in the 1996 EPA AP-42. The current AP-42 factor represents 1st and 2nd stage mote systems combined. The objective of this study was to collect total particulate emission factor data for 1st stage mote 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. Five gins with 1st stage mote system exhausts that were not combined with 2nd stage system exhausts were sampled. The average production rate during testing for the five gins was 27.9 bales/h. The average 1st stage mote system total particulate emission factor based on five tests (15 total test runs) was 0.025 kg/227-kg bale (0.056 lb/500-lb bale). The 1st stage mote system test average emission rates ranged from 0.31 to 1.42 kg/h (0.69-3.13 lb/h).