Impact of CFO Odor and Odor Setback Models
Yingying Hong and Paul Ebner - Purdue Animal Sciences
Odors can have varying effects on different people. There is a growing
consensus that CFO odor, like other odors, at high concentrations can
lead to physical reactions. In most cases, these reactions can lead to what
are called “mood disturbances”, such as changes in mood, stress, etc. One
recent study surveyed 101 adults living within 1.5 miles of at least one
swine CFO over two weeks, and it showed a strong positive association
between self-rated odor intensity and negative moods(Horton 2009).
That is, the higher the odor intensity, the more likely individuals felt
stress, anxiety, and other negative moods. Increases in self-reported
disease symptoms, such as headache, wheezing, and nausea, were also
sometimes observed in CFO neighbors when experiencing intense odor
(O’Connor 2010). Two recent studies (Avery 2004; Wing 2013) have shown
that intense odor can elicit some quantitative responses (e.g., some
immune responses, elevated blood pressure). Many studies showed
that the adverse physical symptoms were more prevalent in individuals
who were highly concerned about CFO odor, indicating that stress could
exacerbate physical symptoms (Donham 2010).
Currently, at the state level, CFOs in Indiana are not regulated based
on odor. However, there are numerous tools available to individuals
involved in CFO siting that are designed to aid in choosing sites where
the CFO would have lowest impact on neighbors, specifically when it
comes to odor. In many cases, community conflict could be significantly
reduced by employing such tools at the onset of deciding where to site
a CFO. The Purdue Agricultural Air Quality Laboratory has developed an
odor setback model(Lim 2000), which incorporates facility size, types
of animals, amount of manure generated, prevailing winds, and odor
abatement practices, among other factors, to recommend setback
distances and predict best locations for CFOs. This model is available to all
Indiana counties. It is updated periodically, and can be accessed here: Livestock Odor Setback Model – Purdue University.
Another commonly used odor setback model is the Minnesota Odor From Feedlots Setback Estimation Tool (OFFSET model; Jacobson 2000). This model
provides a range of setback distances for different
“odor annoyance free frequencies”; defined as
the percentages of time when neighbors will not
experience an odor. In a previous study comparing
five livestock setback estimation models, the setback
distances recommended by the Purdue model were
similar to the distances that provided 94% to 97%
odor annoyance free frequency in the OFFSET model
More studies have confirmed that odor can lead
to physical reactions in people living in proximity
to CFOs. However, these symptoms and the
community conflict they sometimes generate could
be alleviated by using available tools that more
scientifically identify sites where CFO odor will have
the least impact on neighbors.
Avery RC, Wing S, Marshall SW, Schiffman SS. 2004. Odor from Industrial Hog Farming Operations and Mucosal Immune Function in Neighbors. Arch Environ Health. 59(2):101-8.
Donham KJ. 2010. Community and occupational health concerns in pork production: A review. J Anim Sci. 88:E102-11.
Guo H, Jacobson LD, Schmidt DR, Nicolai RE, Janni KA. 2004. Comparison of five models for setback distance determination from livestock sites. Canadian Biosystems Engineering. 46:17-25.
Horton RA, Wing S, Marshall SW, Brownley KA. 2009. Malodor as a Trigger of Stress and Negative Mood in Neighbors of Industrial Hog Operations. Am J Public Health. 99:S610-5.
Jacobson LD, Guo H, Schmidt DR, Nicolai RE, Zhu J, Janni K. 2000. Development of an odour setback determination tool for animal feedlots. ASAE Paper No. 004044. St. Joseph, MI: ASAE.
Lim TT, Heber AJ, Ni JQ, Grant R, Sutton AL. 2000. Odor impact distance guideline for swine production systems. Proceedings of the Water Environment Federation, Odors and VOC Emissions 2000. 16:773-788.
O'Connor AM, Auvermann B, Bickett-Weddle D, Kirkhorn S, Sargeant JM, Ramirez A, Von Essen SG. 2010. The Association between Proximity to Animal Feeding Operations and Community Health: A Systematic Review. PLoS One. 5(3):e9530.
Wing S, Avery Horton RC, Rose KM. 2013. Air Pollution from Industrial Swine Operations and Blood Pressure of Neighboring Residents. Environ Health Perspect. DOI:10.1289/ehp.1205109.