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In recent years, Texas cotton production has represented almost half of all the US cotton production, with most of that production coming from the High Plains. Due to the harsh weather conditions, most cotton on the High Plains is of more storm-proof varieties that are harvested using stripper harvesters. Unlike picker harvesters, which use spindles to remove seed cotton from the boll, stripper harvesters use brushes and bats that indiscriminately remove seed cotton, bolls, leaves, and branches from the plant. As a result, stripper harvested cotton contains more foreign matter than picked cotton and generally contains more immature fibers that are left on the plant by spindle harvesters. Stripper harvesters have several advantages over picker harvesters, including lower purchase prices, fewer moving parts leading to lower fuel and maintenance requirements, and greater efficiency in low yielding cotton. Picker harvesters, however, pick cleaner cotton, are perceived to maintain fiber quality better than strippers, and are able to harvest at higher speeds in high yielding stands. Foreign textile mills continue to raise their standards for fiber quality as cotton spinners are forced to compete with synthetic fibers. Increased yields in the region and higher quality demands have the potential to make harvesting High Plains cotton with pickers an attractive option. The objective of this research is to compare fiber and yarn quality from four varieties of cotton harvested on the High Plains using modern picker and stripper harvesters. [ABSTRACT FROM AUTHOR]

Picker and stripper harvest systems were compared for harvesting irrigated cotton on the High Plains. Four varieties of cotton were harvested using a six-row picker harvester and a six-row stripper harvester with and without field cleaning. A net present value analysis was conducted comparing each harvest system. Inputs for time in motion and fiber quality were determined based on field data from the 2006 and 2007 harvest seasons. [ABSTRACT FROM AUTHOR]

Picker and stripper harvest systems were compared for harvesting irrigated cotton on the High Plains. Stoneville 4554 B2RF was harvested using a picker harvester and a stripper harvester with and without field cleaning. The effect of harvest treatment on foreign matter, fiber quality, and yarn quality were compared. Picked cotton generally had less foreign material, higher micronaire and higher length uniformity than stripped cotton, likely due to the presence of more immature fibers in stripped cotton. Little difference was detected between harvest treatments in carded yarn quality. However, more substantial differences were detected in the quality of carded and combed yarns based on harvest treatment [ABSTRACT FROM AUTHOR]

Picker and stripper harvest systems were compared for harvesting irrigated cotton on the High Plains. Four varieties of cotton were harvested using a six-row picker harvester and a six-row stripper harvester with and without field cleaning. A net present value analysis was conducted comparing each harvest system. Inputs for time in motion and fiber quality were determined based on field data from the 2006 and 2007 harvest seasons. [ABSTRACT FROM AUTHOR]

Picker and stripper harvest systems were compared for harvesting irrigated cotton on the High Plains. Stoneville 4554 B2RF was harvested using a picker harvester and a stripper harvester with and without field cleaning. The effect of harvest treatment on foreign matter, fiber quality, and yarn quality were compared. Picked cotton generally had less foreign material, higher micronaire and higher length uniformity than stripped cotton, likely due to the presence of more immature fibers in stripped cotton. Little difference was detected between harvest treatments in carded yarn quality. However, more substantial differences were detected in the quality of carded and combed yarns based on harvest treatment. [ABSTRACT FROM AUTHOR]

The number of cotton gins in the state of Texas has declined from over 1400 gins in 1960 to less than 280 gins in 2006. Production in the state of Texas has remained relatively constant at 5 million bales except for the 2004/05 and the 2005/06 ginning seasons in which production was boosted to over 7 million bales. Two immediate problems come from the decline in the number of gins and the constant or increased annual production: (1) Remaining gins must gin more seed cotton creating longer ginning seasons; and (2) Seed cotton must be shipped greater distances in order to be ginned with corresponding increases in seed cotton transportation costs. Gin cost surveys from approximately 200 gins and multi-year economic data from over 10 cooperating gins in Texas have provided the base data for the development of decision support software. Preliminary results suggest that the optimum percent utilization for least cost (variable and fixed cost per bale) ginning increases with the ginning rate. It has been hypothesized that this optimum point in the cost-per-bale versus %U relationship will vary for gins processing stripper and picker cotton. Simulation (decision support software) was developed to test hypotheses and to develop recommendations to assist cotton gin managers with engineering and management issues. [ABSTRACT FROM AUTHOR]

Seed cotton transport from the field to the gin is currently accomplished by building modules and hauling them with a module truck. Costs of module transport have not been characterized fully. Engineering economic analyses were performed to develop equations that are used to estimate the cost of module transport based on various assumptions. The use of a semi-tractor trailer (STT) for seed cotton transport is a possibility for reducing costs. Equations also were developed for modeling STT transport costs. Within 15 miles from a gin, the cost of seed cotton transport is $60 per module truck load and $90 per STT load. Outside of 15 miles, the transport costs increased linearly and more rapidly for STT than module truck costs. However, it was assumed that STT would haul 50% more seed cotton per load. The transportation costs of stripper cotton were higher than picker cotton. Comparisons of the module truck versus STT system costs were made using geographic information system (GIS) software. An ArcGIS project was developed using gin location, production areas, highway and road system, and other items of interest. A transport analysis routine in ArcGIS allowed for routing of modules from field to gin and determination of distances. The cost equations developed were used for comparing costs of module transport and STT transport. One transport example where ten fields of seed cotton were transported 150 miles one-way distance to the gin indicated that STT transport cost $9,430 less than module truck transport. [ABSTRACT FROM AUTHOR]

The National Ambient Air Quality Standard (NAAQS) for Particulate Matter (PM) is used to determine attainment and nonattainment. States having nonattainment areas are required by EPA to submit a state implementation plan (SIP). The SIP must describe how the state air pollution regulatory agency (SAPRA) will bring the area back into attainment. In January 2006, the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) submitted its PM10 plan to EPA because the area was classified as serious nonattainment. The plan indicated that significant sources of PM10 would be required to implement Best Available Control Measures/Technology (BACM/BACT) to reduce their emissions. Significant sources were identified for regulation using modeled property line 24-hour PM10 concentrations. The SJVUAPCD claimed that under Rule 2201 in 40 CFR Part 51, a source is defined to be significant if the modeled property line PM10 concentration exceeds an annual significance level of 1 μg/m3 or a 24- hour significance level of 5 μg/m3. The district's interpretation of Rule 2201 caused a dairy operation in the San Joaquin Valley to be identified as a significant source. The dairy was required to purchase $800,000 of emissions offsets to obtain an operating permit. Using dispersion modeling, this paper will demonstrate that it is unlikely that any dairy operation can meet a property line PM10 concentration of 5 μg/m3 and that agricultural operations are being unjustifiably targeted for regulation. [ABSTRACT FROM AUTHOR]

Cyclones are a commonly used air pollution abatement device for separating particulate matter (PM) from air streams in industrial processes. Several mathematical models have been proposed to predict the performance of cyclones as cyclone diameter varies. The objective of this research was to determine the relationship between cyclone diameter, cut point, and slope based on empirical data. Tests were performed comparing cut points and slopes of 15.24-, 30.48-, 60.96-, and 91.44-cm (6-, 12-, 24-, and 36-in.) diameter cyclones with poly-disperse PM having an aerodynamic mass median diameter near 10 μm. The mass of PM collected by the cyclones and the mass and particle size distributions of PM that penetrated the cyclones were used to determine the cut point and slope of each cyclone. The cut points of cyclones showed no relationship to cyclone diameter, while the slope of cyclones increased as cyclone diameter increased with statistically different collection efficiencies observed among the 30.48- , 60.96-, and 91.44-cm (12-, 24-, and 36-inch) diameter cyclones. None of the previously published mathematical models analyzed in this paper accurately predicted cyclone cut point. [ABSTRACT FROM AUTHOR]

Wind tunnel testing is required by USEPA for evaluating Particulate Matter samplers. In the past, most wind tunnel studies employed mono-dispersed aerosols as test particulate matter. Compared to the mono-dispersed aerosols, using poly-dispersed particles have two primary advantages: (1) better simulation of the performance of samplers in the real world and (2) significantly reduced experimental time and cost. A new wind tunnel testing protocol has been developed to use poly-dispersed particles. This paper will discuss dispersion of the test particulate matter, sampler/filter quality assurance, sample analysis, and data processing. The sampling protocol was employed to test sampler model BGI PQ100/200 PM10. Initial results of sampler cut point and slope will be presented. [ABSTRACT FROM AUTHOR]

Cyclones are a commonly used air pollution abatement device for separating particulate matter (PM) from air streams in industrial processes. Several mathematical models have been proposed to predict the performance of cyclones as cyclone diameter varies. The objective of this research was to determine the relationship between cyclone diameter, cut point, and slope based on empirical data. Tests were performed comparing cut points and slopes of 15.24-, 30.48-, 60.96-, and 91.44-cm (6-, 12-, 24-, and 36-in.) diameter cyclones with poly-disperse PM having an aerodynamic mass median diameter near 10 μm. The mass of PM collected by the cyclones and the mass and particle size distributions of PM that penetrated the cyclones were used to determine the cut point and slope of each cyclone. The cut points of cyclones showed no relationship to cyclone diameter, while the slope of cyclones increased as cyclone diameter increased with statistically different collection efficiencies observed among the 30.48- , 60.96-, and 91.44-cm (12-, 24-, and 36-inch) diameter cyclones. None of the previously published mathematical models analyzed in this paper accurately predicted cyclone cut point. [ABSTRACT FROM AUTHOR]

Seed cotton transport from the field to the gin is currently accomplished by building modules and hauling them with a module truck. Costs of module transport have not been characterized fully. Engineering economic analyses were performed to develop equations that are used to estimate the cost of module transport based on various assumptions. The use of a semi-tractor trailer (STT) for seed cotton transport is a possibility for reducing costs. Equations also were developed for modeling STT transport costs. Within 15 miles from a gin, the cost of seed cotton transport is $60 per module truck load and $90 per STT load. Outside of 15 miles, the transport costs increased linearly and more rapidly for STT than module truck costs. However, it was assumed that STT would haul 50% more seed cotton per load. The transportation costs of stripper cotton were higher than picker cotton. Comparisons of the module truck versus STT system costs were made using geographic information system (GIS) software. An ArcGIS project was developed using gin location, production areas, highway and road system, and other items of interest. A transport analysis routine in ArcGIS allowed for routing of modules from field to gin and determination of distances. The cost equations developed were used for comparing costs of module transport and STT transport. One transport example where ten fields of seed cotton were transported 150 miles one-way distance to the gin indicated that STT transport cost $9,430 less than module truck transport. [ABSTRACT FROM AUTHOR]

The National Ambient Air Quality Standard (NAAQS) for Particulate Matter (PM) is used to determine attainment and nonattainment. States having nonattainment areas are required by EPA to submit a state implementation plan (SIP). The SIP must describe how the state air pollution regulatory agency (SAPRA) will bring the area back into attainment. In January 2006, the San Joaquin Valley Unified Air Pollution Control District (SJVUAPCD) submitted its PM10 plan to EPA because the area was classified as serious nonattainment. The plan indicated that significant sources of PM10 would be required to implement Best Available Control Measures/Technology (BACM/BACT) to reduce their emissions. Significant sources were identified for regulation using modeled property line 24-hour PM10concentrations. The SJVUAPCD claimed that under Rule 2201 in 40 CFR Part 51, a source is defined to be significant if the modeled property line PM10 concentration exceeds an annual significance level of 1 μg/m3 or a 24- hour significance level of 5 μg/m3. The district's interpretation of Rule 2201 caused a dairy operation in the San Joaquin Valley to be identified as a significant source. The dairy was required to purchase $800,000 of emissions offsets to obtain an operating permit. Using dispersion modeling, this paper will demonstrate that it is unlikely that any dairy operation can meet a property line PM10 concentration of 5 μg/m3 and that agricultural operations are being unjustifiably targeted for regulation. [ABSTRACT FROM AUTHOR]

Wind tunnel testing is required by USEPA for evaluating Particulate Matter samplers. In the past, most wind tunnel studies employed mono-dispersed aerosols as test particulate matter. Compared to the mono-dispersed aerosols, using poly-dispersed particles have two primary advantages: (1) better simulation of the performance of samplers in the real world and (2) significantly reduced experimental time and cost. A new wind tunnel testing protocol has been developed to use poly-dispersed particles. This paper will discuss dispersion of the test particulate matter, sampler/filter quality assurance, sample analysis, and data processing. The sampling protocol was employed to test sampler model BGI PQ100/200 PM10. Initial results of sampler cut point and slope will be presented. [ABSTRACT FROM AUTHOR]

Gin managers are under increasing pressure from state departments of transportation concerning seed cotton module transport. Module trucks are over height, width and weight restrictions for most cotton producing states. Exceptions are allowed in many cases. Still, the module truck loaded with a module exceeds tandem axle weight limits for Interstate Highway travel. No exceptions are given. An alternative to the module truck is the semi-tractor trailer (STT). Fully-loaded an STT would not exceed height, width, or even weight restrictions. STT may reduce the cost of transporting seed cotton compared to conventional module transporting with module trucks. However, modifications to the module formation system would be necessary to utilize the STT transport system economically. For a fifty mile round trip haul, an STT transport cost model predicts a $5.30 per bale cost and a corresponding module truck transport cost model predicts a $6.84 per bale cost. Other costly elements of module transportation include the routing of trucks and the locating of modules in fields. A geographic information system (GIS) software package, ArcGIS, has the capability to route trucks along shortest distance, quickest route or alternate roads to pick up modules in the field and return to the gin. A research program for developing a transport tool using ArcGIS is in progress at Texas A&M University. Cotton production, ginning facilities, interstate highways, state highways and local roads in the state of Texas have been mapped using ArcGIS. Color near infrared (NIR) aerial photos have been uploaded as well. The transport analyst feature in ArcGIS will allow for analyses of gin service areas, regional transport ability and ultimately cost evaluations for transport. [ABSTRACT FROM AUTHOR]

ISCST3 has been the preferred model of the Environmental Protection Agency (EPA) to estimate concentrations of particulate matter (PM) at or beyond the property line of sources emitting PM such as cotton gins. The modeled concentrations can be used to limit emissions from stationary and fugitive sources. The regulatory limits of PM include limits for PM10, PM2.5, and coarse PM (PMcoarse). Beginning in November 2006, the EPA will begin transitioning to the use of AERMOD for predicting concentrations on the basis that AERMOD more accurately characterizes the planetary boundary layer. Both AERMOD and ISCST3 use a Gaussian plume model to predict concentrations, but AERMOD has a more detailed set of meteorological inputs. The dispersion modeling program chosen by EPA to predict property line concentrations will have a direct effect on the cotton ginning industry. Each model may yield different results. Inaccurate predictions of property line concentrations for cotton gins could result in the unjust denial of air quality permits. It is important that the predicted downwind concentrations using ISCST3 and AERMOD be evaluated relative to appropriate regulations of the cotton ginning industry. [ABSTRACT FROM AUTHOR]

Gin managers are under increasing pressure from state departments of transportation concerning seed cotton module transport. Module trucks are over height, width and weight restrictions for most cotton producing states. Exceptions are allowed in many cases. Still, the module truck loaded with a module exceeds tandem axle weight limits for Interstate Highway travel. No exceptions are given. An alternative to the module truck is the semi-tractor trailer (STT). Fully-loaded an STT would not exceed height, width, or even weight restrictions. STT may reduce the cost of transporting seed cotton compared to conventional module transporting with module trucks. However, modifications to the module formation system would be necessary to utilize the STT transport system economically. For a fifty mile round trip haul, an STT transport cost model predicts a $5.30 per bale cost and a corresponding module truck transport cost model predicts a $6.84 per bale cost. Other costly elements of module transportation include the routing of trucks and the locating of modules in fields. A geographic information system (GIS) software package, ArcGIS, has the capability to route trucks along shortest distance, quickest route or alternate roads to pick up modules in the field and return to the gin. A research program for developing a transport tool using ArcGIS is in progress at Texas A&M University. Cotton production, ginning facilities, interstate highways, state highways and local roads in the state of Texas have been mapped using ArcGIS. Color near infrared (NIR) aerial photos have been uploaded as well. The transport analyst feature in ArcGIS will allow for analyses of gin service areas, regional transport ability and ultimately cost evaluations for transport. [ABSTRACT FROM AUTHOR]

ISCST3 has been the preferred model of the Environmental Protection Agency (EPA) to estimate concentrations of particulate matter (PM) at or beyond the property line of sources emitting PM such as cotton gins. The modeled concentrations can be used to limit emissions from stationary and fugitive sources. The regulatory limits of PM include limits for PM10, PM2.5, and coarse PM (PMcoarse). Beginning in November 2006, the EPA will begin transitioning to the use of AERMOD for predicting concentrations on the basis that AERMOD more accurately characterizes the planetary boundary layer. Both AERMOD and ISCST3 use a Gaussian plume model to predict concentrations, but AERMOD has a more detailed set of meteorological inputs. The dispersion modeling program chosen by EPA to predict property line concentrations will have a direct effect on the cotton ginning industry. Each model may yield different results. Inaccurate predictions of property line concentrations for cotton gins could result in the unjust denial of air quality permits. It is important that the predicted downwind concentrations using ISCST3 and AERMOD be evaluated relative to appropriate regulations of the cotton ginning industry. [ABSTRACT FROM AUTHOR]

Cyclones are the most commonly used air pollution abatement device for separating particulate matter (PM) from air streams in agricultural processes such as cotton gins. This paper describes a system and the experimental design that will be used to empirically determine the relationship between the diameter and performance of 1D3D cyclones. Six, 12, 24, and 36 inch cyclones will be tested using a polydisperse PM with an aerodynamic mass median diameter near ten microns. The mass of PM collected by the cyclones and the mass of PM that penetrates the cyclones and is deposited on a set of filters will be used to determine the collection efficiency of each cyclone. The objective of this research is to develop a model to accurately characterize the change in cyclone performance with changes in cyclone diameter based on empirical data. [ABSTRACT FROM AUTHOR]

An engineering approach to analyze PM dry deposition due to gravitational settling is summarized in this paper. Particle horizontal settling distance is determined based upon wind speed and particle terminal settling velocity. New PSD in the downwind plume is calculated based upon particle horizontal settling distance and source PSD. Results of this research indicate that change of PSD in the downwind plume is a function of wind speed, downwind distance and source PSD. Both MMD and GSD in the downwind plume decrease with increase of downwind distance and source MMD. When the MMD of the source is high, there was a big change in the MMD and GSD of the dust in the downwind plume. Likewise, there was a big change in the MMD and GSD of dust in the downwind plume as downwind distance is increased. However, the change of wind speed has an inverse impact on the change of downwind PSD. MMD and GSD in the downwind plume decrease with decrease of wind speed. Gravitational settling causes significant change of MMD and GSD in the downwind plume and thus, has significant impact on the PM10 sampling error problems. Future research is needed to quantify this impact for more accurate PM10 measurement. [ABSTRACT FROM AUTHOR]

The number of operating cotton gins in Texas has steadily declined in the past 40 years from 1400 to less than 280 while the production of cotton has remained at approximately 4-5 million bales. In order to market the 5 million bales with fewer gins, the remaining gins will be processing more seed cotton in the future. It is likely that the cotton ginning industry will be faced with longer seasons with associated issues relative to variable and fixed costs, transporting modules longer distances from farm to the gin and finding acceptable methods of at least partially paying producers for the cotton lint and seed value. These changes in the harvesting/ginning interface will likely result in a new system of handling and ginning of seed cotton. The goal of this study is to utilize a systems engineering approach to analyze scenarios that could help cotton producers and cotton ginners achieve an optimum system that would be economically attractive for the future of the cotton industry. Results from this study have shown that the fixed cost per bale follows a negative exponential trend as the percentage utilization of gin is increased. The average fixed cost per bale was estimated to be about $30 while the average variable cost was estimated at $20 per bale following the assumptions used. The average total cost was estimated at about $50/bale. A relationship was developed relating the total cost of gin operations as a function of utilization rates for the different ginning rate categories. This initial result provided a general trend on how the operation of cotton gins could be made more efficient. The term "percent utilization" of a gin is defined in this study. One-hundred percent (100%) utilization is the ginning rate multiplied by 0.8 efficiency and 1000 hours. It is anticipated that this mathematical descriptor may be used in the future for management decision support. It may be possible for gins to take advantage of economies of scale in their ginning operations. The immediate consequence of ginning more cotton with fewer gins will be the expected transport issues associated with moving large numbers of seed cotton modules over longer distances and the problem of transporting them utilizing the Interstate Highway System. This will be the topic for subsequent systems analysis work. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The control of particulate matter emissions from cotton gins is a priority in many states. The air pollution regulatory process requires that concentrations measured off-property be less than the National Ambient Air Quality Standards. Two methods are commonly used to determine the concentrations on or beyond the property line: ambient sampling and dispersion modeling. In order to limit the emissions from a cotton gin, the State Air Pollution Regulatory Agencies require that the gin obtain a permit. This permit sets the Allowable Emission Rate for the primary criteria pollutant of concern, particulate matter with an aerodynamic equivalent diameter of ten microns or less. The Environmental Protection Agency (EPA) has established emission factors for the particulate emissions from cotton gins in its AP-42 document. When using dispersion modeling or measuring ambient mass concentrations downwind of a cotton gin to determine if it is meeting its allowable emission rate, it is important to note that there are two sources of particulate matter. The exhaust systems from the machinery used to extract the cotton and bale is the source that is being permitted. The gin yard and roads also produce particulate matter. However, these sources are considered to be fugitive emissions, and are not regulated unless the source is considered to be a major source under the Title V operating permit program. There are no cotton gins that currently meet the threshold to be considered a Title V major source, so these emissions should not be regulated. It was hypothesized by the authors that the gin yard and road emissions can contribute significantly to the downwind concentrations. This was demonstrated using the EPA-approved Gaussian-based model, Industrial Source Complex Short Term Version 3 (ISCST3). With this dispersion model, it was possible to distinguish between sources and the concentrations resulting from those sources. The emissions from the gin yard and roads were estimated using AP-42 emission factors, and applied using two processes that are described in detail in the methods section. The average contribution of the gin yard and road uncontrolled emissions was found to be as high as 35% based upon the processes and model assumptions. While this contribution is not precisely what is found on an actual gin yard, it does demonstrate the necessity of including the gin yard and road emissions when determining the concentrations off-property. [ABSTRACT FROM AUTHOR]

Air pollution regulations are forcing many producers and processors of agricultural products to implement control practices for fugitive particulate matter (PM) emissions. Often the effectiveness of the required practices is unknown. USDA conservation programs offer cost sharing opportunities for producers to implement environmental control practices. An accurate estimation of environmental benefits is needed for prioritization of conservation resources. There is a need to understand and quantify fugitive PM control methods and their effectiveness to ensure that environmental improvement resources yield maximum benefit. This paper evaluates the common sources and the most effective control methods based on available literature. This paper also identifies areas where data is missing and discusses the ramifications of regulating with scarce data. [ABSTRACT FROM AUTHOR]

Cyclone separators are widely used in cotton gins as air pollution abatement devices. The Texas A&M Cyclone Design method is a simple method for designing cyclones based on an inlet design velocity. The Texas A&M Cyclone Design method specifies "ideal" inlet velocities of 3200 feet per minute (fpm) and 3000 fpm for 1D3D and 2D2D cyclones, respectively. There is evidence that higher collection efficiencies may be obtained from cyclones using higher inlet velocities that those specified as the "ideal" velocity, but this increased efficiency comes at the expense of increased pressure drop. This paper quantifies the inlet velocities at which maximum collection efficiencies are obtained for 1D3D and 2D2D cyclones and the marginal pressure drop associated with reaching these higher collection efficiencies. [ABSTRACT FROM AUTHOR]

The number of operating cotton gins in Texas has steadily declined in the past 40 years from 1400 to less than 280 while the production of cotton has remained at approximately 4-5 million bales. In order to market the 5 million bales with fewer gins, the remaining gins will be processing more seed cotton in the future. It is likely that the cotton ginning industry will be faced with longer seasons with associated issues relative to variable and fixed costs, transporting modules longer distances from farm to the gin and finding acceptable methods of at least partially paying producers for the cotton lint and seed value. These changes in the harvesting/ginning interface will likely result in a new system of handling and ginning of seed cotton. The goal of this study is to utilize a systems engineering approach to analyze scenarios that could help cotton producers and cotton ginners achieve an optimum system that would be economically attractive for the future of the cotton industry. Results from this study have shown that the fixed cost per bale follows a negative exponential trend as the percentage utilization of gin is increased. The average fixed cost per bale was estimated to be about $30 while the average variable cost was estimated at $20 per bale following the assumptions used. The average total cost was estimated at about $50/bale. A relationship was developed relating the total cost of gin operations as a function of utilization rates for the different ginning rate categories. This initial result provided a general trend on how the operation of cotton gins could be made more efficient. The term ‘percent utilization’ of a gin is defined in this study. One-hundred percent (100%) utilization is the ginning rate multiplied by 0.8 efficiency and 1000 hours. It is anticipated that this mathematical descriptor may be used in the future for management decision support. It may be possible for gins to take advantage of economies of scale in their ginning operations. The immediate consequence of ginning more cotton with fewer gins will be the expected transport issues associated with moving large numbers of seed cotton modules over longer distances and the problem of transporting them utilizing the Interstate Highway System. This will be the topic for subsequent systems analysis work. [ABSTRACT FROM AUTHOR]

An engineering approach to analyze PM dry deposition due to gravitational settling is summarized in this paper. Particle horizontal settling distance is determined based upon wind speed and particle terminal settling velocity. New PSD in the downwind plume is calculated based upon particle horizontal settling distance and source PSD. Results of this research indicate that change of PSD in the downwind plume is a function of wind speed, downwind distance and source PSD. Both MMD and GSD in the downwind plume decrease with increase of downwind distance and source MMD. When the MMD of the source is high, there was a big change in the MMD and GSD of the dust in the downwind plume. Likewise, there was a big change in the MMD and GSD of dust in the downwind plume as downwind distance is increased. However, the change of wind speed has an inverse impact on the change of downwind PSD. MMD and GSD in the downwind plume decrease with decrease of wind speed. Gravitational settling causes significant change of MMD and GSD in the downwind plume and thus, has significant impact on the PM10 sampling error problems. Future research is needed to quantify this impact for more accurate PM10 measurement. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The control of particulate matter emissions from cotton gins is a priority in many states. The air pollution regulatory process requires that concentrations measured off-property be less than the National Ambient Air Quality Standards. Two methods are commonly used to determine the concentrations on or beyond the property line: ambient sampling and dispersion modeling. In order to limit the emissions from a cotton gin, the State Air Pollution Regulatory Agencies require that the gin obtain a permit. This permit sets the Allowable Emission Rate for the primary criteria pollutant of concern, particulate matter with an aerodynamic equivalent diameter of ten microns or less. The Environmental Protection Agency (EPA) has established emission factors for the particulate emissions from cotton gins in its AP-42 document. When using dispersion modeling or measuring ambient mass concentrations downwind of a cotton gin to determine if it is meeting its allowable emission rate, it is important to note that there are two sources of particulate matter. The exhaust systems from the machinery used to extract the cotton and bale is the source that is being permitted. The gin yard and roads also produce particulate matter. However, these sources are considered to be fugitive emissions, and are not regulated unless the source is considered to be a major source under the Title V operating permit program. There are no cotton gins that currently meet the threshold to be considered a Title V major source, so these emissions should not be regulated. It was hypothesized by the authors that the gin yard and road emissions can contribute significantly to the downwind concentrations. This was demonstrated using the EPA-approved Gaussian-based model, Industrial Source Complex Short Term Version 3 (ISCST3). With this dispersion model, it was possible to distinguish between sources and the concentrations resulting from those sources. The emissions from the gin yard and roads were estimated using AP-42 emission factors, and applied using two processes that are described in detail in the methods section. The average contribution of the gin yard and road uncontrolled emissions was found to be as high as 35% based upon the processes and model assumptions. While this contribution is not precisely what is found on an actual gin yard, it does demonstrate the necessity of including the gin yard and road emissions when determining the concentrations off-property. [ABSTRACT FROM AUTHOR]

Air pollution regulations are forcing many producers and processors of agricultural products to implement control practices for fugitive particulate matter (PM) emissions. Often the effectiveness of the required practices is unknown. USDA conservation programs offer cost sharing opportunities for producers to implement environmental control practices. An accurate estimation of environmental benefits is needed for prioritization of conservation resources. There is a need to understand and quantify fugitive PM control methods and their effectiveness to ensure that environmental improvement resources yield maximum benefit. This paper evaluates the common sources and the most effective control methods based on available literature. This paper also identifies areas where data is missing and discusses the ramifications of regulating with scarce data. [ABSTRACT FROM AUTHOR]

Cotton gins are required to obtain operating permits from state air pollution regulatory agencies (SAPRA) which regulate the amount of particulate matter that can be emitted. Industrial Source Complex Short Term version 3 (ISCST3) is the Gaussian dispersion model currently used by some SAPRAs to predict downwind concentrations used in the regulatory process in the absence of field sampling data. The maximum ambient concentrations for PM10 and PM25 are set by the National Ambient Air Quality Standard (NAAQS) at 150 μg/m³ and 65 μg/m³ respectively. Some SAPRAs use the NAAQS concentrations as property line concentrations for regulatory purposes. This paper reports the results of a unique approach to estimating downwind PM10 and PM25 concentrations using Monte Carlo simulation, the Gaussian dispersion equation, the Hino Power Law, and a particle size distribution that characterizes the dust typically emitted from cotton gin exhausts. These results were then compared to a ten minute concentration (C10) and the concentrations that would be theoretically measured by a FRM PM10 and PM25 sampler. The total suspended particulate (TSP) emission rate, particle size distributions, and sampler performance characteristics were assigned to triangular distributions to simulate the real world operation of the gin and sampling systems. The TSP emission factor given in AP-42 for cotton gins was used to derive the PM mass emission rate from a 40 bale per hour plant. The Gaussian equation was used to model the ambient TSP concentration downwind from the gin. The performance characteristics for the PM10 and PM25 samplers were then used to predict what the measured concentration would be for two PSD conditions. The first PSD assumption was that the mass median diameter (MMD) and geometric standard deviation (GSD) were constant at 12μm and 2 and the second scenario assigned a triangular distribution to the MMD and GSD of {15, 20, 25} μm and {1.8, 2.0, 2.2} respectively. The results show that the PM2.5 fraction of the dust emitted under either PSD condition was negligible when compared to the NAAQS for PM2.5 of 65 μg/m3. The results also demonstrate that correcting for wind direction changes within the hour using the power law reduces the ambient concentration by a factor of 2.45. The measured downwind concentrations from the samplers reported higher 24-hour averages for each of the ten days modeled than the concentrations predicted by the new model. [ABSTRACT FROM AUTHOR]

The US Environmental Protection Agency is in the process of assessing the need for a National Ambient Air Quality Standard for the coarse fraction of particulate material (PMCF). Specifically, the PM indicator being considered is particulate matter between 2.5 and 10 μm in aerodynamic equivalent diameter (AED). EPA is primarily relying on the available epidemiological studies that examine the possible health effects of PMCF to reach a decision about developing a coarse particulate matter standard. These epidemiological studies utilize data from size selective PM samplers to estimate the study population's exposure to each PM indicator as defined by EPA (PM10, PM25, and PMCF). Epidemiological studies typically focus on urban populations in order to obtain sufficient sample size and to increase statistical certainty associated with study findings. Because of this focus on the urban environment, there has been a lack of studies that evaluate the effect of coarse particulate matter in rural environments on human health. There are a number of key differences between the urban and rural environments in the United States that can lead to critical mistakes in applying data from urban studies to the rural environment. These include differences in particle sources, which affect particle size distribution and composition, differences in the concentration of gaseous co-pollutants, and differences in PM sampler performance in the two environments. It is our contention that these differences between the urban and rural environment are significant and that the epidemiological studies cited by EPA rely on data that are not representative of the rural environment. These factors raise serious concerns that the implementation of a PMCF standard in the rural environment will impose an unfair and unwarranted regulatory burden on the businesses and citizens in the rural areas. [ABSTRACT FROM AUTHOR]

The EPA approved federal reference methods (FRM) for measuring particulate matter concentrations of PM10 and PM25 are affected by the particle size distribution (PSD) of the particulate matter (PM) present in ambient air. The PSD of PM in the ambient air emitted by agricultural operations (rural areas) is significantly larger than that of PM present in urban areas. Typically, urban PM will have a mass median diameter (MMD) less than 10 μm aerodynamic equivalent diameter (AED) whereas, agricultural PM will have an MMD larger than 10 μm AED. An MMD of as high as 24 μm AED has been reported for PM emitted through agricultural operations. The EPA- approved FRM PM10 and PM25 samplers have been shown to exhibit over-sampling problems for particles having MMDs of greater than 10 μm such as agricultural dust. As a consequence, agricultural operations are not being regulated fairly. This work presents some procedures that can be done to correct this over sampling problem. [ABSTRACT FROM AUTHOR]

The FRM ambient PM10 sampler does not always measure the true PM10 concentration. There are inherent sampling errors associated with the PM10 samplers due to the interaction of particle size distribution and sampler performance characteristics. These sampling errors, which are the relative differences between theoretical estimation of the sampler concentration and the true concentration, should be corrected for equal regulation between industries. An alterative method of determines true PM10 concentration is to use the TSP concentration and PM10 fraction of PSD in question. This paper reports a new theoretical method to correct PM10 sampling errors for a true PM10/TSP ratio. The new method uses co-located PM10/TSP samplers' measurement to derive the MMD of PSD and true PM10/TSP ratio. Correction equations and charts have been developed for the PM's with GSD's of 1.2, 1.3, … 2.1, respectively and the PM10 sampler with a cut-point of 10 μm and slope of 1.5. These equations and charts can be used to obtain a corrected PM10/TSP ratio for the given GSD and sampler characteristics. The corrected PM10/TSP ratio will be treated as true PM10/TSP ratio for PM10 concentration calculations. This theoretical process to obtain a corrected PM10/TSP ratio will minimize the inherent PM10 sampler errors and will provide more accurate PM10 measurement for the given condition. [ABSTRACT FROM AUTHOR]

Gravimetric measurement of particulate matter (PM) concentrations in ambient environments is the basis for regulation of PM fractions (i.e. PM10 and PM25) under the Federal Clean Air Act. While the measurement is straight forward, inherent elements of uncertainty enter the analysis, resulting in much larger uncertainty in the concentration calculation. This paper discusses the importance of uncertainty approximation and analyzes the uncertainty inherent in a gravimetric PM concentration measurement. Utilizing a first order Taylor Series approximation and analytical derivatives, the overall system uncertainty is computed. Additionally, this paper uses a sensitivity analysis of the contributing uncertainty elements in order to identify the most critical measurements and their implications on the calibration, operation, and design of PM samplers. [ABSTRACT FROM AUTHOR]

The regulation of particulate matter (PM) emitted by agricultural sources (cotton gins, feed mills, concentrated animal feeding operations (CAFOs) is based upon downwind concentrations of particulate matter less than 10 and 2.5 micrometers (μm) (PM10 and PM25) aerodynamic equivalent diameter (AED). Both PM10 and PM25 samplers operate by pre-separating PM larger than the size of interest (10 and 2.5 μm) prior to capturing the PM on the filter. It has been shown that Federal Reference Method (FRM) PM10 and PM25 samplers have concentration measurement errors (Buser et al, 2001, 2002) when sampling PM in ambient air having mass median diameters (MMD) larger than the size of interest. It has also been demonstrated that most PM from agricultural sources typically have particle size distributions with MMDs larger than 10 μm (AED). The PM10 concentration measurement error can be as much as 343% for ambient PM with an MMD=20 μm. These errors are a consequence of the PM10 pre-separator allowing a larger mass of PM greater than 10 μm to penetrate to the filter than the mass of PM less than 10 μm captured by the pre-separator. The mass of the particles greater than 10 μm that are allowed to penetrate to the filter, introduce a substantial error in the calculated concentration of PM10. Pargmann et al (2001) reported that sampling PM larger than 2.5 μm (AED) resulted in a shift in the cut-point of the pre-separator. If this is true for all PM10 and PM25, samplers, the resulting errors in measurements of ambient concentrations could be even larger than those reported by Buser. One solution to this problem is to measure the concentration of total suspended particulate matter (TSP) and calculate the concentration of PM10 by determining the mass fraction of PM less than size of interest from the particle size distribution (PSD). The "standard" high volume (TSP) sampler operates at a volume rate-of-flow in excess of 40 cubic feet per minute (cfm) (EPA, 1987b). Most of the current PM10 and PM25 samplers operate at one cubic meter per hour (cmh). (1 cmh = 0.589 cfm.) McFarland (1983) reported that TSP samplers have a "cut-point" of a nominal 45 μm (AED). EPA specifies the engineering design parameters for TSP samplers in 40CFR Part 50 (1987b). This paper reports the engineering design and evaluation of a low-volume (0.589 cfm) TSP sampler (TSPLV). The results suggest that this new TSPLV may be more robust and more accurate that the "standard" high volume (TSP) sampler. [ABSTRACT FROM AUTHOR]

Cotton gins are required to have an air quality permit in order to operate. Some states permit gins are based upon predicted PM10 concentration levels from dispersion modeling. The use of dispersion modeling allows regulators to estimate downwind concentrations that potentially could impact the public off-property. Industrial Source Complex - Short Term version 3 (ISCST3) is the EPA approved dispersion modeling program used by most states to regulate industrial sources. The product of ISCST3 is a 24-hour average downwind concentration of particulate matter given an emission rate. Concentrations predicted by ISCST3 are based upon the Gaussian dispersion model, using Pasquill-Gifford dispersion parameters (σy, σz) It is generally known that ISCST3 over-predicts downwind concentration from low-level point sources (LLPS) such as cotton gins, grain elevators and feed mills. ISCST3 does not account for horizontal wind direction variations within an hour. Accounting for these variations results in a significantly lower predicted PM10 concentration at the receptor. This paper describes a unique approach for estimating 24-hour concentrations using USEPA (2000) data on horizontal wind direction variations, Monte-Carlo simulations, and the Gaussian model. The results include power law coefficients by stability class for estimating 60-minute concentrations from 10-minute concentrations (Gaussian equation) and the ratios of C60/C10 for 10 days of meteorological data. It is concluded that the current downwind concentrations estimated by regulatory agencies using ISCST3 over-predicts PM10 by a factor of 2.5. [ABSTRACT FROM AUTHOR]

The faculty at the Center for Agricultural Air Quality Engineering and Science over the past few decades developed a method of accurately determining particulate matter concentrations from industries that emit air pollution. The CCM method of characterizing the size distribution of aerosols has shown that the EPA approved PM10 and PM2.5 samplers over sample agricultural dusts. New methods of determining particulate matter size distributions are continuously sought out for possible use. This study compares two new methods - A and B - to the CCM method. All three methods have distinct advantages and disadvantages for use in agricultural settings. Method A's disadvantages were found to outweigh its advantages and therefore will not be investigated further. Method B shows promise as an instrument for use in agricultural applications. However, differences between the sizes reported compared to the CCM for two separate dusts indicate that more testing should be performed on Method B with a different distribution system. [ABSTRACT FROM AUTHOR]

Two identical PM10 pre-separators, along with two identical low-volume (1m3/hr) total suspended particulate (TSP) samplers and two identical high-volume (85m3/hr) TSP samplers were tested side-by-side in a controlled laboratory dust chamber. The test results show that PM10 samplers over-sample when exposed to ambient PM having mass median diameters (MMD's) larger than 10 micrometers aerodynamic equivalent diameter (AED). The cut-points and slopes of PM10 pre-separator changed with the change of MMD's of inlet particulate matter (PM). The fractional efficiency curve shifted to the right with the decrease of the MMD of the inlet PM. Analysis of the results suggest that co-locating PM10 and TSP samplers may offer a process that can be used to correct for PM10 sampler error. [ABSTRACT FROM AUTHOR]

Agriculture is currently facing more restrictive emission limits as a consequence of air quality regulations. A number of State Air Pollution Regulatory Agencies (SAPRAs) are focusing their efforts on particulate matter (PM) emissions from field operations. In particular, PM emissions from concentrated animal feeding operations (CAFO) are of concern. The problem with regulating air emissions from ground-level area sources (GLAS) is the lack of accurate emission flux data. This is partially due to the difficulties of directly measuring the emission rate of dust from a given source. In order to quantify the emissions from agricultural operations, net downwind concentrations are measured and the resulting concentrations are used to back into an emission flux using dispersion modeling. Emission fluxes can subsequently be reported as emission factors. One use of emission factors is for permitting new and existing sources. According to the EPA, "Modeling is the preferred method for determining emissions limitations for both new and existing sources," (EPA, 1999). It should be expected that emission factors will be used to estimate downwind concentrations using dispersion modeling and that the resulting estimated concentrations will be used in the air pollution regulatory process. The box model has been used in the past to estimate fluxes with the resulting fluxes being used in Industrial Source Complex-Short Term, Version 3 (ISC) to estimate downwind concentrations for regulatory purposes. This paper presents a proposed process for estimating fluxes using the box model with the criterion that the subsequent concentrations with ISC will be conservative. [ABSTRACT FROM AUTHOR]

The air pollution regulatory process involves the permitting of sources of regulated pollutants. Part of the permit process requires sources to demonstrate that the National Ambient Air Quality Standards (NAAQS) are not exceeded as a result of pollutant release. While ambient air sampling may be used to demonstrate compliance with the NAAQS, a source's right to operate is becoming increasingly dependent primarily on dispersion modeling results. Currently used Gaussian based dispersion models do not adequately account for pollutant dispersion resulting from sub-hourly variations in wind speed and direction. This can result in over-estimates of downwind concentration, which may result in costly additional control measures or operating permit being denied. Low elevation releases and close property line boundaries cause low-level agricultural sources, such as cotton gins, to be very sensitive to inappropriate modeling results. This research focused on the issue of developing a methodology to analyze the theoretical degree of dispersion within sub-hourly intervals. The degree of dispersion was based on small time-interval (15 second) meteorological data. Using the results of this analysis a new model that accounts for plume dispersion due to sub-hourly variation in wind speed and direction, was developed. The new model (FTAM) was compared to the currently used regulatory models ISC3 and AERMOD, using concentration predictions downwind of a source typical of a cotton gin. FTAM 24-hour concentrations were generally lower that ISC3 predicted 24-hour concentrations, and similar or slightly higher than AERMOD predicted 24-hour concentrations. [ABSTRACT FROM AUTHOR]

Agricultural operations across the United States are encountering difficulties in complying with the current air pollution regulations for particulate matter (PM). The National Ambient Air Quality Standards (NAAQS) for PM in terms of PM2.5, are ambient air concentration limits set by EPA that should not be exceeded. Further, State Air Pollution Regulatory Agencies (SAPRA's) utilize the NAAQS to regulate criteria pollutants emitted by industries by applying the NAAQS as property line concentration limit. The primary NAAQS are health-based standards and therefore, an exceedance implies that it is likely that there will be adverse health effects for the public. Since the proposal of the PM2.5 regulation, numerous journal articles and technical references have been written to discuss the epidemiological effects, trends, regulation, methods of determining PM2.5, etc. A common trend among many of these publications is the use of samplers to collect information on PM2.5. All too often, the sampler data are assumed to be an accurate measure of PM2.5. The fact is that issues such as sampler uncertainties, environmental conditions, and material characteristics for which the sampler is measuring must be incorporated for accurate sampler measurements. The focus of this manuscript is on the errors associated with the particle size distribution (PSD) characteristics of the material in the air that is being sampled, sampler performance characteristics, the interaction between these two characteristics, and the effect of this interaction on the regulatory process. Theoretical simulations were conducted to determine the range of errors associated with this interaction for the PM2.5 sampler. Results from these simulations indicated that a source emitting PM characterized by a mass median diameter (MMD) of 20 μm and a geometric standard deviation (GSD) of 1.5 could be forced to comply with a 14 times more stringent regulation than a source emitting PM characterized by a MMD of 10 μm and a GSD of 1.5. Therefore, in order to achieve equal regulation among differing industries, PM2.5 measurements MUST be based on true concentration measurements. [ABSTRACT FROM AUTHOR]

Currently, total suspended particulate (TSP) high volume samplers use axial flow fans to draw a sample of particulate matter that collects onto a glass filter. These samplers have an inherent error of the airflow variation with the axial flow fans. A new sampler design has been developed and tested by the Texas A&M University Biological and Agricultural Engineering Department. The design of the TAMU HiVol TSP Sampler integrates ease of use and allows for more consistent flow rates. A centrifugal fan is used to pull air through a filter cartridge. This corrects for the error of airflow variation with the axial flow fans. With the centrifugal fan, Teflon filters may be used in place of glass fiber filters. By using Teflon filters, the particle size distribution (PSD) of the filtrate can be found directly using a particle sizer such as the Beckman Coulter-Counter Multisizer 3. It is difficult to obtain accurate PSDs for PM captured on glass fiber filters because the background particulate matter from the filter media can confound the results. From the PSD, the mass fraction of PM10 and PM2.5 can be determined. As an added convenience, the new sampler design incorporates an improved method of changing filters and allows for easy storage, setup and takedown. [ABSTRACT FROM AUTHOR]

An abstract of the article "Evaluation of TEOM Method for the Measurement of Particulate Matter," by Stewart J. Skloss, Bryan W. Shaw, Calvin B. Parnell is presented.