Joint information of the Minnesota Department of Agriculture (MDA) and Minnesota Pollution Control Agency (MPCA).
Odor impacts are difficult to predict. Downwind odors are a function of the amount and type of emissions source, weather conditions and topography. The impact these odors have is also a function of the distance to the neighbors.
Dealing with odor is a complex issue and agencies such as the Minnesota Pollution Control Agency (MPCA), Minnesota Department of Health (MDH), Minnesota Department of Agriculture (MDA) and research institutions such as the University of Minnesota are currently assessing odor mitigation technologies and are researching best management practices.
Livestock producer groups in Minnesota have also been active in promoting the use of odor reducing technologies and have been proponents of utilizing science and research to develop odor mitigation methods. Livestock producers are also becoming familiar with newer technologies to reduce odor emissions and are actively working with their producer groups and often partner with research institutions to conduct odor mitigation research.
Currently, the State of Minnesota only regulates Hydrogen Sulfide (H2S) and Particulate Matter (PM) emissions from livestock operations. H2S is regulated through the state H2S ambient air standard. This standard is a 30-minute average of 30 parts per billion (ppb) found twice in five days, or a 30-minute average of 50 ppb found twice per year. Odor is not regulated by the State at the present time.
The MPCA is responsible for enforcing H2S and PM. The MPCA utilizes a hand held unit called a Jerome Meter to screen for H2S. Jerome meters cannot be used to establish a legal violation of the standard; this requires continuous air monitoring. When H2S emissions are exceeded, the MPCA may utilize a Continuous Air Monitor (CAM) to further monitor H2S emissions in the field for an extended period of time.
It should be noted that a variety of factors can affect the accuracy of CAM results. Livestock operators that are emptying liquid manure storage areas and are land applying the manure are exempt from H2S standards for 21 days during a calendar year. MPCA Odor Policy.
Although the MPCA currently has no rule or law that regulates ammonia emissions, the MDH has established a Health Risk Value for ammonia.
Some counties in Minnesota utilize an assessment tool called Odors From Feedlots Setback Estimation Tool (OFFSET) to determine the downwind odor impacts of a livestock operation. OFFSET was developed by the University of Minnesota and is based on science and research.
Counties may also enact specific zoning requirements to ensure that new residential development does not take place in agricultural areas. Many counties already require conditional use permits for larger livestock operations and are able to work with the livestock producers to ensure compliance with county specific odor mitigation standards.
Potential new homeowners in rural areas should be aware of the sights, sounds and smells of country living before moving into rural areas. Researching the area where you may be building and talking with county planning and zoning staff or the County Feedlot Officer (CFO) for more information about where livestock operations are located is a good first step. The CFO and county staff can discuss things you need to know about living in or near highly intensive agricultural areas.
Livestock producers are implementing a number of Best Management Practices and strategies to control odor, gas and dust emissions. These technologies and strategies include ensuring that organic crusts are maintained on open air liquid manure storage structures, developing and implementing odor management plans, injecting or immediately incorporating manure in accordance with a comprehensive nutrient management plan and disposing of spoiled feed in a timely manner.
Livestock producers also utilize other technologies such as biofilters, biocurtains, methane digesters, innovative ventilation systems, use feed additives and properly dispose of dead animals. Windbreaks are also installed to control dust and assist in the dispersion of odorous gases. Modern swine facilities now utilize under barn deep pits versus open liquid manure storage structures of the past. Livestock producers also work with their local CFO to be in compliance with county and state feedlot rules and regulations.
Livestock producers inform their neighbors about manure hauling schedules during the manure pumping season, which is generally in the spring and fall of the year.
The costs vary for implementing newer odor reducing technologies and Best Management Practices (BMPs) and many factors can affect final project costs. On the lower end of the spectrum, a comprehensive nutrient management plan may cost $1,500 to $2,500 to initially develop while a methane digester may cost hundreds of thousands of dollars to engineer, construct and maintain.
The costs for some newer technologies such as methane digesters are relatively high. However the ability to become more energy self-reliant and eligibility for carbon credits may offset some of the costs. Livestock producers are continually striving to find alternative odor reducing technologies and BMPs that are effective and economically feasible.
Odor Research and Management
Larry Jacobson, Professor
Bioproducts and Biosystems Engineering, University of Minnesota
Feedlot Siting Issues
Jim Ostlie, Livestock Development and Planning Specialist
Ag Marketing & Development Division