This report is part of a project to characterize cotton gin emissions from the standpoint of total particulate stack sampling and particle size analyses. In 2006 and again in 2013, the United States (U.S.) Environmental Protection Agency (EPA) published a more stringent National Ambient Air Quality Standard for particulate matter with nominal diameter less than or equal to 2.5 µm (PM2.5). This created an urgent need to collect additional cotton gin emissions data to address current regulatory issues, because EPA AP-42 cotton gin PM2.5 emission factors were limited. In addition, current EPA AP-42 emission factor quality ratings for cotton gin PM10 (particulate matter with nominal diameter less than or equal to 10 µm) data are questionable, being extremely low. The objective of this study was to characterize particulate emissions for mote trash systems from cotton gins across the cotton belt based on particle size distribution analysis of total particulate samples from EPA-approved stack sampling methods. Average measured of PM2.5, PM6, and PM10 emission factors based on the mass and particle size analyses of EPA Method 17 total particulate filter and wash samples from two gins (6 total test runs) were 0.00031 kg/227-kg bale (0.00068 lb/500-lb bale), 0.0023 kg/bale (0.0051 lb/bale), and 0.0042 kg/bale (0.0093 lb/bale), respectively. The mote trash system particle size distributions were characterized by an average mass median diameter of 23.9 µm (aerodynamic equivalent diameter). Based on system average emission factors, the ratio of PM2.5 to total particulate was 1.75%, PM6 to total particulate was 13.3%, and PM10 to total particulate was 24.2%.
