Development of Cotton Gin Burr Pile PM10 Emission Factor

Abstract

The need for higher rated emission factors due to increasing regulation of particulate matter by the EPA led to a previously conducted study that developed new emission factors for all point sources at cotton gins. However, an emission factor for the gin burr pile, an area source, had not yet been developed. Developing this emission factor was a high priority due to predicted increases in regulative scrutiny directed towards cotton gin emissions. Using sampled ten-micron particulate matter, PM10, concentration data an emission factor for cotton gin burr piles was backcalculated with the aid of AERMOD, an EPA approved gaussian dispersion model. Models were developed for the cotton gin in which the sampling took place. AERMOD models were built to consider local and upper atmospheric meteorological data, terrain data, building downwash effects, and all known PM10 point sources on the gin site. The modeled PM10 concentration values were then compared to the sampled PM concentration values using a left tailed Z-test at a 95% confidence level. Based on the Z-test a modeled emission rate of 2.5 lbs/hr best matched the onsite sampled PM10 concentrations. The emission factor of 2.5 lbs/hr is equivalent to 0.07353 lbs/bale, since the models were based on an average ginning rate of 34 bales/hr. The model assumes all sampled PM10 in the air that is not due to other known point sources is caused by the gin burr pile. This leads to the model being conservative since all fugitive emissions are attributed to the burr pile. Overprediction of the emission factor is much more acceptable than underprediction, so the models were built to avoid underprediction.