Particle Size Distribution Analysis of Cotton Gin Dust and Its Impact on PM10 Concentration Measurements. Manuscript prepared for presentation at the 2005 Beltwide Cotton Conferences. National Cotton Council

Low volume FRM PM10 and TSP (total suspended particulate) samplers were collocated and operated directly downwind from a cotton gin's main sources of emissions while the facility was in full operation. The particle size distribution and concentration of dust collected by the TSP sampler were used to determine the true PM10 concentrations and compare them with the PM10 concentrations measured by the low volume PM10 sampler. Results showed that in all instances, the concentrations measured by the PM10 sampler were in error and higher than the PM10 concentrations obtained from using the TSP sampler. A linear relationship existed between the true PM10 concentration and the concentration from the PM10 sampler. Specifically, the results of this study have indicated the following: (a) 55 % of the PM10 concentration reported by the FRM PM10 sampler was considered true PM10 throughout the range of PM concentration measured; (b) 35 % of the TSP sampler concentration comprised PM10; (c) the lognormal distribution accurately described the PSD of the cotton gin dust; and (d) the use of the TSP sampler followed by measurement of mass median diameter (MMD) and geometric standard deviation (GSD) was found to be a better approach in reporting PM10 concentrations of agricultural dusts such as that from cotton gins