@article{shah_westerman_munilla_adcock_baughman_2008, title={Design and evaluation of a regenerating scrubber for reducing animal house emissions}, volume={51}, DOI={10.13031/2013.24217}, abstractNote={Animal houses can emit substantial quantities of air pollutants. Compared with other pollutants, ammonia is emitted from animal houses in relatively large quantities and can have adverse public health and environmental impacts. This article describes the development and evaluation of a novel scrubber prototype, consisting of an endless polypropylene screen running in a trough of alum solution, that could be used to reduce ammonia emissions from animal houses. When building exhaust ventilation air contacts the screen, ammonia is dissolved in the aqueous solution on the screen and transported into the trough. Low ammonia concentration ( 66 h of evaluation under low and high concentration conditions, with a weighted average airflow rate of 0.93 m3 s-1 and velocity of 0.52 m s-1, the scrubber reduced ammonia emissions by 58.3%. Compared with commercial spray and packed column scrubbers used in industry, it had a lower pressure drop (~110 Pa). It also had a low water consumption of ~1 mL m-3 treated air. Further evaluation of the scrubber in different types of animal houses and for different pollutants is required. Its design should be improved to increase ammonia removal efficiency and reduce pressure drop, footprint size, and cost. There is also need to model gas transfer in this type of scrubber.}, number={1}, journal={Transactions of the ASABE}, author={Shah, Sanjay and Westerman, P. W. and Munilla, R. D. and Adcock, M. E. and Baughman, G. R.}, year={2008}, pages={243–250} }
 @article{bottcher_keener_munilla_williams_schiffman_2004, title={DUST AND ODOR EMISSIONS FROM TUNNEL VENTILATED SWINE BUILDINGS IN NORTH CAROLINA AND COMPARISON OF DIFFERENT ODOR EVALUATION METHODS}, volume={20}, ISSN={1943-7838}, url={http://dx.doi.org/10.13031/2013.16064}, DOI={10.13031/2013.16064}, abstractNote={Tunnel ventilation of swine buildings conveys odorous dust and gases out of the production buildings. Measurement of dust and odor levels and other environmental parameters is necessary for characterizing emissions and evaluating control options. During evaluations of odor control systems, measurements of dust and odor levels in building inlet and exhaust air were obtained. Odor and dust levels were consistent with data obtained in other states and Europe. Odor concentrations and emission rates were based on odor measurements from the Duke University Taste and Smell Laboratory at several dilution levels, as well as a calibration curve for odor panelists based on swine manure odor. The computed odor concentration based on measurements over a range of dilutions was greater than the predicted odor concentration based on the calibration curve, for two field visits. This result may be due to odorous dust particles increasing odor persistence above that of vaporous odorants from swine manure. Odor measurements were also obtained using headspace sampling of unaspirated and aspirated cotton swatches. Aspirating the swatches increased odor intensity compared to unaspirated swatches and improved correlation with air sample odor intensities.}, number={3}, journal={Applied Engineering in Agriculture}, publisher={American Society of Agricultural and Biological Engineers (ASABE)}, author={Bottcher, R. W. and Keener, K. M. and Munilla, R. D. and Williams, C. M. and Schiffman, S. S.}, year={2004}, pages={343–347} }
 @article{keener_zhang_bottcher_munilla_2002, title={Evaluation of thermal desorption for the measurement of artificial swine odorants in the vapor phase}, volume={45}, DOI={10.13031/2013.11063}, abstractNote={Quantification of odorants from animal production facilities is difficult. The current technique is to collect air 
samples in Tedlar bags and quantify odor using a trained olfactory panel. In this approach, relative differences between 
samples can be determined, but further quantification of odorants is limited. An alternative approach is to quantify odorants 
in air emissions using sorbent tubes. A sorbent tube is a glass tube packed with a specific adsorbent material (Tenax TA, 
Carboxen 1000, Carbosieve SIII, etc.) and has been used to collect volatiles and quantify emissions from various industrial 
sources. Each adsorbent has a limited range of chemical selectivity. Limited applications of sorbent tubes with single or dual 
adsorbents have been used to measure odorant emissions from animal production facilities. 
In this study, tri–packed sorbent tubes and Tedlar bags were compared in characterizing 19 major odorants found in 
artificial swine odor. The sorbent tubes were packed with Tenax TA, Carboxen 1000, and Carbosieve SIII. The artificial swine 
odor was directly desorbed onto the tri–packed sorbent tube. For comparison, a 10–L Tedlar bag was filled with nitrogen gas 
and artificial swine odor. The Tedlar bag was then desorbed onto the tri–packed sorbent tube. The sorbent tube was then 
thermally desorbed into a gas chromatography (GC) system with a flame ionization detector (FID) for quantification. The 
tri–packed sorbent tube demonstrated recoveries greater than 74% and detection limits less than 0.4 ng for all 19 odorants. 
Thus, a tri–packed sorbent tube may provide an analytical method to measure low concentrations of major odorants found 
in air emissions from swine production facilities. Tedlar bags showed limited recoveries of some odorants, less than 12% for 
indole and skatole. In addition, Tedlar bags immediately sampled after three flushings with nitrogen emitted 3.50 ng L–1 hr–1 
of acetic acid (~35% above background levels) and 2.13 ng L–1 hr–1 phenol (~27% above background levels). These results 
suggest that air samples collected in Tedlar bags may bias olfactory analysis.}, number={5}, journal={Transactions of the ASAE}, author={Keener, K. M. and Zhang, J. and Bottcher, R. W. and Munilla, R. D.}, year={2002}, pages={1579–1584} }
 @article{oehrl_keener_bottcher_munilla_connelly_2001, title={Characterization of odor components from swine housing dust using gas chromatography}, volume={17}, DOI={10.13031/2013.6911}, abstractNote={A method was developed for the determination of odor–causing compounds in swine housing dust. Dust samples 
were extracted with methanol while heating to 60 

 
C. After partitioning, the methanol containing the compounds of interest 
was analyzed by gas chromatography (GC) using flame ionization detection (FID). Efficiency of extraction was proven by 
spike recovery. Samples of dust from houses treated with various odor–controlling systems were compared to untreated 
controls. This method allowed for relative comparisons of odor compounds that could be used to evaluate the effectiveness 
of engineering systems to control dust and odor.}, number={5}, journal={Applied Engineering in Agriculture}, author={Oehrl, L. L. and Keener, K. M. and Bottcher, R. W. and Munilla, R. D. and Connelly, K. M.}, year={2001}, pages={659–661} }
 @article{bottcher_munilla_baughman_keener_2000, title={Designs for windbreak walls for mitigating dust and odor emissions from tunnel ventilated swine buildings}, ISBN={1892769107}, DOI={10.13031/2013.83}, abstractNote={Although windbreak walls have traditionally been applied to reduce ground-level wind speeds and enhance snow deposition, windbreak walls have also recently been placed downwind of animal buildings in efforts to control emissions of dust and odors. In particular, windbreaks placed near exhaust fans on tunnel-ventilated livestock and poultry buildings appear promising, primarily because the air jets issuing from the exhaust fans are diverted upward. This effect promotes mixing of the odorous, dusty airflow with the wind passing over the building, so that the plumes of air pollutants originating from the fans are made larger (extend higher). Thus it is reasonable to expect that in some wind conditions the aerial concentration of odorous vapors, dust, and other air pollutants in the breathing space of downwind neighbors will be reduced by improvement in air mixing at the emission sources (the fans). Windbreak structures may either be designed to withstand the same wind speeds as the buildings and be insured with the buildings, or lower wind speeds at reduced cost. Relevant design considerations and low-cost designs using UV-resistant tarpaulin or plastic material, roofing, or wood fastened to anchored pipe frames or posts are discussed. If the windbreaks are not designed for maximum design wind speeds, a method of ensuring non-catastrophic failure is needed, such as breakaway ties fastening material to frames. The location of the windbreak affects the diversion of airflow from exhaust fans. Further modeling and field evaluations are needed to determine beneficial and potential adverse effects of fan plume deflection. Observations of windbreak action in several locations suggest that the windbreaks should be placed two to four fan diameters downwind from the fans to deflect fan airflow without back pressures, and extend high enough to fully intercept the plumes of airflow issuing from the fans (e.g. 4 m high for typical buildings).}, journal={Swine housing : proceedings of the first international conference : October 9-11, 2000, Des Moines, Iowa}, publisher={St. Joseph, Mich. : American Society of Agricultural Engineers}, author={Bottcher, R. W. and Munilla, R. D. and Baughman, G. R. and Keener, K. M.}, year={2000}, pages={174} }
 @article{bottcher_keener_munilla_williams_schiffman_2000, title={Dust and odor emissions from tunnel ventilated swine buildings in North Carolina}, ISBN={1892769123}, journal={Air pollution from agricultural operations : proceedings of the 2nd international conference, October 9-11, 2000, Des Moines, Iowa}, publisher={St. Joseph, Mich. : American Society of Agricultural Engineers}, author={Bottcher, R. W. and Keener, K. M. and Munilla, R. D. and Williams, C. M. and Schiffman, S. S.}, year={2000}, pages={196} }
 @article{bottcher_keener_munilla_williams_schiffman_2000, title={Scent of a swine building: Tunnel ventilation problems test engineers' ingenuity}, volume={7}, ISBN={1076-3333}, number={10}, journal={Resource, Engineering & Technology for a Sustainable World}, author={Bottcher, R. W. and Keener, K. M. and Munilla, R. D. and Williams, C. M. and Schiffman, S. S.}, year={2000}, pages={13} }