Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/5/2005
Publication Date: 6/20/2005
Citation: Capareda, S.C., Buser, M.D., Whitelock, D.P., Green, J.K., Parnell, Jr., C.B., Shaw, B.W., Wanjura, J.D. 2005. Particle size distribution analysis of cotton dust and its impact on PM10 concentration measurements. In: Proceedings of the Beltwide Cotton Conference, January 4-7, 2005, New Orleans, Louisiana. p. 631-642. 2005 CDROM.
Interpretive Summary: Previous research has focused on the theoretical errors associated with EPA approved PM10 ambient air samplers. This study provides actual data showing that EPA approved PM10 ambient air samplers will greatly over-estimate the true PM10 being emitted from cotton gins. The over-sampling reported from this research is larger than the theoretical errors previously reported, indicating that the performance characteristics of the PM10 ambient air samplers are varying beyond the established tolerances. In general, the true PM10 concentrations were found to be roughly 55% of the PM10 sampler concentrations. Sampler errors of this magnitude will result in cotton gins being regulated at a much more stringent level than urban based sources and adjustments must be made to assure that all industries are equally regulated.
Technical Abstract: Low volume Federal Reference Method (FRM) PM10 and total suspended particulate (TSP) samplers were collocated and operated in a plume of PM emissions being emitted from a cotton gin while the gin was in full operation. These samplers were not located at the gin's property line boundary, as the purpose of the study was not to compare the gin's emission to the National Ambient Air Quality Standards. The purpose of the study was to determine the extent to which FRM PM10 samplers over sample when exposed cotton gin particulate matter (PM) emissions at various concentration loadings. Concentrations collected from FRM PM10 samplers were compared to true PM10 concentrations that were obtained by performing gravimetric and particle size analysis on filters obtained from collocated low volume TSP samplers. The tests showed that the FRM PM10 samplers over sampled the true PM10 in all test replications and that a linear relationship existed between the true PM10 and the FRM PM10 sampler concentration. Results from the study indicated that: (a) 55% of the PM10 FRM PM10 sampler concentration is true PM10; (b) 35% of the TSP sampler concentration is true PM10; and (c) the lognormal distribution accurately describes the particle size distribution of cotton gin particulate matter emissions. In general, the FRM PM10 ambient air samplers are overestimating the true PM10 emissions being emitted from cotton gins and all sampler concentration measurements obtain downwind from cotton gins should be critically evaluated.