Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/2013
Publication Date: 12/30/2013
Publication URL: http://handle.nal.usda.gov/10113/5418160
Citation: Buser, M.D., Whitelock, D.P., Boykin Jr, J.C., Holt, G.A. 2013. Unloading system PM2.5 emission factors and rates for cotton gins: Method 201A combination PM10 and PM2.5 sizing cyclones. Journal of Cotton Science. 17(4):309-319.
Interpretive Summary: In 2006, the US Environmental Protection Agency implemented a more stringent air quality standard for very fine dust smaller than 2.5 micrometers in diameter. All cotton gins will eventually be impacted by this standard. The primary issue affecting the cotton industry across the country is that cotton gins may not be regulated fairly, because very little scientifically sound information is available on cotton gin emissions of this very fine dust. In response, seven cotton gins at locations across the Cotton Belt were sampled by the three USDA-ARS Cotton Ginning Laboratories and Oklahoma State University to determine the amount of very fine dust emitted while processing cotton. Three of the seven gins had unloading systems that were not combined with other systems. It was found that the unloading systems at the gins sampled emitted on average 0.049 pounds of the fine dust for every 500-pound bale of cotton produced, which was about 18% of the total dust emitted from the system. This information provides previously unavailable estimates for fine dust emissions from cotton gins and, thus, will ensure that cotton gins are appropriately permitted and accounted for in state and federal regulations. Furthermore, this may allowing many gins to avoid installing additional dust control measures with substantially higher capital and operating costs that will impact the ginning cost to the farmer.
Technical Abstract: This manuscript is part of a series of manuscripts that detail a project to characterize cotton gin emissions from the standpoint of stack and ambient sampling. The impetus behind the project was the 2006 EPA implementation of a more stringent standard for particulate matter less than or equal to 2.5 micrometers (PM2.5) and the fact that there was very little available cotton gin PM2.5 emissions data. The objective for this study was the development of PM2.5 emission factors for cotton gin unloading systems based on the EPA-approved stack sampling methodology, Other Test Method 27. The project plan included sampling seven cotton gins across the Cotton Belt. Key factors for selecting specific cotton gins included: 1) facility location (geographically diverse), 2) industry representative production capacity, 3) typical processing systems, and 4) equipped with properly designed and maintained 1D3D cyclones. Three of the seven gins had unloading systems that used pneumatic conveyance and had exhaust airstreams that were not combined with another system. In terms of capacity, the three gins were typical of the industry, averaging 24.2 bales/hr during testing. Average measured PM2.5 emission factor based on the three tests (8 total test runs) was 0.022 kg/bale (0.049 lb/bale). The project emission factors for PM10 and total particulate were 0.071 kg/bale (0.157 lb/bale) and 0.120 kg/bale (0.265 lb/bale), respectively. The PM2.5 emission rate from test averages ranged from 0.35 to 0.71 kg/hr (0.76 to 1.56 lb/hr). The ratios of PM2.5 to total particulate, PM2.5 to PM10, and PM10 to total particulate were 18.4, 31.0, and 59.4%, respectively.