Submitted to: Transactions of the ASAE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2003
Publication Date: 2/20/2004
Citation: Hughs, S.E., Buser, M.D., Isom, R. Emission factors for first- and second-pick Pima cotton. Transactions of the American Society of Agricultural Engineers. 2004. v. 47(1). p. 29-35.
Interpretive Summary: Cotton gins are regulated as to the amount of particulate (PM) emitted while processing cotton. Cotton gin regulation is done by assigning emission factors, expressed in terms of pounds of PM per bale, to each gin air exhaust. Average emission factors have been developed for each gin exhaust through many years of source testing. Most of these source tests were done while 1st pick upland cotton was being processed. Region 9 of the Environmental Protection Agency is concerned that 2nd pick Pima cotton may result in emissions that are higher than the established emission factors. Source testing was done at a commercial cotton gin while processing both 1st and 2nd pick Pima cotton. The tests showed that the 1st pick Pima emissions were equal to or lower than the established emission factors and the 2nd pick Pima emissions were lower than the 1st pick emissions. The result is that processing 2nd pick Pima should not result in a PM emissioon problem for a commercial gin.
Technical Abstract: EPA's Region 9, which includes the major Pima production areas of California and Arizona, raised the concern of possible emission factor differences between 1st and 2nd pick Pima cotton. Anecdotal evidence indicated that some complaints of excessive particulate emissions from Pima gins have arisen from the processing of 2nd pick cotton. A lot of emission factor information has been developed over the past 20 years for gin processing of cotton. While some of this data probably includes some second pick upland, most of the upland harvest is once over with no second picking. There has also been emission factor data gathered for Pima gins, but none of this data can be verified to be from 2nd pick Pima. Due to the market value of the Pima fiber, there is a significant amount of 2nd pick Pima cotton ginned each year in EPA Region 9. A scientific study was conducted at a commercial roller gin during the 2001 ginning season to determine what differences there were, if any, between the emission factors for 1st and 2nd pick Pima cotton. Source testing was conducted on the first seed cotton cleaning and drying system, which is one of the heaviest in terms of particulate emissions. This replicated source test showed that all measured emission parameters were lowest for the 2nd pick Pima cotton. This result indicates that there do not need to be separate particulate emission factors for 1st and 2nd pick Pima.