Search

This study supplemented the National Air Emissions Monitoring Study (NAEMS) with one year of comprehensive measurements of odor emission at five swine and four dairy buildings. The measurements included both standard human sensory measurements using dynamic forced-choice olfactometry and chemical analysis of the odorous compounds using gas chromatography-mass spectrometry. In this article, multilinear regressions between odor and gas concentrations (a total of 20 compounds including H2S, NH3, and VOCs) were investigated. Regressions between odor and gas emission rates were also tested. It was found that gas concentrations, rather than emission rates, should be used to develop multilinear regression models. For the dairy sites, H2S, NH3, acetic acid, propanoic acid, 2-methyl propanoic, and pentanoic acids were observed to be the compounds with the most significant effect on sensory odor. For the swine sites, in addition to these gases, higher molecular weight compounds such as phenol, 4-methyl phenol, 4-ethyl phenol, and 1H-indole were also observed to be significant predictors of sensory odor. When all VOCs were excluded from the model, significant correlations between odor and H2S and NH3 concentrations were still observed. Although these coefficients of determination were lower when only H2S and NH3 were used, they can be used to predict odor variability by up to 83% when VOC data are unavailable. [ABSTRACT FROM AUTHOR]

This study was an add-on project to the National Air Emissions Monitoring Study (NAEMS) and focused on comprehensive measurement of odor emissions considering variations in seasons, animal types, and olfactometry laboratories. Odor emissions from four of 14 NAEMS sites with nine barns/rooms (two dairy barns at the WI5B and IN5B sites, two pig finishing rooms at IN3B, and two sow gestation barns and a farrowing room at the IA4B site) were measured during four 13-week cycles. Odor emissions were reported per barn area (OU h-1 m-2), head (OU h-1 head-1), and animal unit (OU h-1 A U-1). The highest overall odor emission rates were measured in summer (1.2 x 105 OU h-1 m-2, 3.5 x 105 OU h-1 head-1, and 6.2 x 105 OU h-1 AU-1), and the lowest rates were measured in winter (2.5 x 104 OU h-1 m-2, 9.1 x 104 OU h-1 head-1, and 1.5 x 105 OU h-1 AU-1). The highest ambient odor concentrations and barn odor emissions were measured from the sow gestation barns of the IA4B site, which had unusually high H2S concentrations. The most intense odor and the least pleasant odor were also measured at this site. The overall odor emission rates of the pig finishing rooms at IN3B were lower than the emission rates of the IA4B sow gestation barns. The lowest overall barn odor emission rates were measured at the IN5B dairy barns. However, the lowest ambient odor concentrations were measured at the ventilation inlets of the WI5B dairy barns. [ABSTRACT FROM AUTHOR]

Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include inputs to odor setback models, while chemical emission factors may be compared with regulation thresholds as a means of demonstrating potential health impacts. A companion study of the National Air Emissions Monitoring Study (NAEMS) included measurements necessary for establishing odor and chemical emission factors for confined animal feeding operations. This additional investigation was conducted by the University of Minnesota, Iowa State University, West Texas A&M Agri-Life Center, and Purdue University. The objectives were to (1) determine odor emission rates across swine and dairy facilities and seasons using common protocols and standardized olfactometry methods, (2) develop a chemical library of the most significant odorants, and (3) correlate the chemical library with the olfactometry results. This document describes the sampling and quality assurance methods used in the measurement and evaluation of odor and chemical samples collected at two freestall dairy farms, one sow (gestation/farrowing) facility, and one finishing pig site. Odor samples were collected in Tedlar bags and chemical samples were collected in sorbent tubes at barn inlet and exhaust locations using the NAEMS multiple-location gas sampling systems. Quality assurance protocols included interlaboratory comparison tests, which were evaluated to identify variations between olfactometry labs. While differences were observed, the variations among the labs and samples appeared random and the collected odor data were considered reliable at a 0.5% level of statistical significance. Overall, the study took advantage of groundbreaking opportunities to collect and associate simultaneous odor and chemical information from swine and dairy buildings while maintaining accordance with standard methods and comparability across laboratories. [ABSTRACT FROM AUTHOR]

Biofiltration is a proven method to reduce odor and gas emissions from swine buildings and manure storage units. Biofilter media selection and moisture content fluctuations significantly influence biofilter performance. The purpose of this study was to test corn cobs as an alternative biofilter media because wood chips may become less available in the future due to the spread of emerald ash borer disease. In addition, a naturally occurring adsorbent (diatomaceous shale) was tested as an additive to manage biofilter media moisture content. Five 1 m × 1 m × 1 m biofilter cells were built to treat pit fan exhaust air from a swine finishing barn. A semi-continuous sampling system was used to measure the biofilters' inlet and outlet gas concentrations. Results showed that all of the biofilters were effective, reducing H2S emissions on average by 7.3% to 50.1% and reducing NH3 emissions on average by 9.8% to 86.3%. The corn cobs were less dense and more porous than the wood chips and had lower pressure drop per unit depth. Adding 15% diatomaceous shale to the corn cobs helped manage media moisture and improved H2S and NH3 reduction efficiencies. However, after 16 months of media aging, high levels of N2O generation were observed during two sampling days. The estimated media cost with 15% diatomaceous shale was $0.52 per m³ h-1 ($0.89 per cfm) of air treated. The corn cobs cost (100% corn cob biofilter) was $0.03 per m³ h-1 ($0.05 per cfm) of air treated. [ABSTRACT FROM AUTHOR]

Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically significant pathogen in the swine industry that can spread through the air. Many swine gestation and farrowing barns with negative-pressure ventilating systems filter the inlet air to manage airborne PRRSV transmission using MERV 8 pre-filters in series with either MERV 14 or MERV 16 filters. Recent research reported air infiltration rates for a new 3,000-sow gestation/farrowing swine barn at several static pressure levels. The barn infiltration data and supplier-provided airflow versus pressure drop data for the filters, a fan, and an evaporative cooling pad were used to model steady-state virus particle concentrations inside a wellmixed barn. Other model inputs included the inside temperature, design ventilating rate, a fan performance factor, filter area, a filter airflow reduction factor due to particulate matter accumulation, and ambient virus particle concentration distributions. For the conditions used, model results indicated that higher barn virus concentrations were obtained with lower mechanical ventilating rates and higher barn infiltration rates. Improved fan performance reduced the number of fans needed but had little impact on barn virus concentrations. Increasing the filter area reduced the pressure drop that the fans had to overcome at higher ventilating rates and correspondingly reduced the unfiltered infiltration rates and barn virus concentrations. Reduced airflow due to particulate matter accumulation on the filters increased the system pressure drop, increased the number of fans running, and increased the barn virus concentrations. Model results indicated that filter combinations that reduced overall virus penetration reduced barn virus concentrations by 57% to 80% for the conditions modeled. More work is needed to assess the model results and the importance of the adjusted factors for other barn and equipment conditions. [ABSTRACT FROM AUTHOR]