Agriculture, Ecosystems and Environment 149 (2012) 154–163 Contents lists available at SciVerse ScienceDirect Agriculture, Ecosystems and Environment jo u r n al hom ep age: www.elsevier.com/locate/agee Odor mitigation with tree buffers: Swine production case study  Guillermo Hernandez a,b , Steven Trabue a,∗ , Thomas Sauer a , Richard Pfeiffer a , John Tyndall c a USDA Agriculture Research Service, Ames, IA 50011, USA b Soil and Water & Environment Group, The New Zealand Institute for Plant & Food Research Limited, Lincoln, New Zealand c Department of Natural Resource and Ecology Management, Iowa State University, Ames, IA 50011, USA a r t i c l e i n f o Article history: Received 1 December 2010 Received in revised form 28 November 2011 Accepted 1 December 2011 Available online 31 January 2012 Keywords: Odor Particulate Shelterbelt Swine Tree buffer VOCs a b s t r a c t Vegetative environmental buffers (VEB) are a potentially low cost sustainable odor mitigation strategy, but there is little to no data supporting their effectiveness. Wind tunnel experiments and field monitoring were used to determine the effect VEB had on wind flow patterns within a swine facility. Particle and odorous compound concentrations were monitored before and after the VEB. Wind tunnel experiments indicated that building orientation had about the same impact on air flow patterns as the combined build- ings and VEB. Field monitoring studies revealed that air flow patterns at a swine facility were dynamic showing intense instability during the heat of the day, but stable air in the evening hours indicating that air during the day was controlled by vertical movement into the atmosphere while in the evening air pat- terns show a collapse mostly horizontal movement. Total particle counts before and after the vegetative buffer were reduced by over 40% and odorous compound concentrations for volatile fatty acids, phenol and indole compounds were reduced by 40–60%. Plant material taken from trees in the vegetative buffer showed no significant loading gradients between materials facing the swine facility and those opposite the swine facility. There were significantly higher loadings of odorous VFAs, phenolic, and indole com- pounds on plant material for samples taken from 2.7 m compared to samples taken from either 0.6 or 1.3 m indicating that vertical transport was major transport mechanism for odor at the swine facility. Published by Elsevier B.V. 1. Introduction Odor emissions associated with confined animal production have been identified as one of the most significant animal emission at the local level (NRC, 2003) and continues to be a significant chal- lenge for the livestock industries. Swine production in particular is a primary source of citizen complaints (Huang and Miller, 2006) and odor nuisance lawsuits in this region have recently reached an all- time high (Heber and Bogan, 2006). Odors from swine production facilities have been linked to lower quality of life (Thu et al., 1997; Wing et al., 2008), loss of property values in surrounding commu- nities (Palmquist et al., 1997) as well as concern that odors can have far reaching negative impact on the overall mental and social well- being of rural communities (Donham et al., 2007). All in all, it has been said that the future of the swine industry will be shaped by its collective ability to improve environmental impact technologies specifically those that effectively mitigate odors (Honeyman, 1996;  Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and use of the name by the USDA implies no approval of the product to the exclusion of others that may be suitable. ∗ Corresponding author. Tel.: +1 515 294 0201; fax: +1 515 294 1209. E-mail address: steven.trabue@ars.usda.gov (S. Trabue). Hogberg et al., 2005). As such, the sustainability of the economically critical pork industry in the U.S. Midwest as well as the social health of rural communities is at stake with regard to mitigation research. Complicating this issue there are no federal laws on the regu- lation of odors in the United States, and the measures that many states take (e.g., legal separation distances) have been largely inef- fective (Tyndall et al., in press). Therefore producers are tasked with adopting effective mitigation technology. Yet odor mitigation has long been challenging due to the inherent physico-chemical com- plexity of odors and the odor transport mechanisms. Currently, there are over 400 compounds associated with swine production (Schiffman et al., 2001; O’Neill and Phillips, 1992; Spoelstra, 1980), yet only a few of these compounds are thought to be responsi- ble for odor (Zahn et al., 2001; Wright et al., 2005; Trabue et al., 2011a). To date, no single compound has been linked as a surro- gate to odor despite several efforts to identify such a compound. In addition, there is little linkage between major odor compound class emission concentrations (Trabue et al., 2011a). This has made the quantification of odor challenging due to the complexity of com- pounds associated with odor. Currently, odors are thought to be transported by one of two ways either through vapor phase trans- port directly or through attachment onto particulate matter. There is some evidence that both mechanisms are at play (Schiffman et al., 2001; Bottcher, 2001; Cai et al., 2006); however, the contribution of each is difficult to determine. Consequently, solutions to odor 0167-8809/$ – see front matter. Published by Elsevier B.V. doi:10.1016/j.agee.2011.12.002