Spring 2002
Report addresses animal production and air quality concerns
by Gerald Miller, College of Agriculture
A new report addresses public health and environmental concerns about air emissions from concentrated animal feeding operations (CAFOs). The report, which was requested by State of Iowa government officials, was written by faculty members at Iowa State University (ISU) and the University of Iowa (UI).
The report was delivered in early February to the Iowa Department of Natural Resources (DNR), which had charged the universities to consider whether there was scientific evidence for establishing standards for air quality. Also, the DNR asked the universities to address other science-based issues regarding CAFOs.
The report's recommendations are based upon the best science available to ensure that rural air is as free of risk as possible to protect public health, ensure quality of life for rural areas, preserve the environment for all Iowans, and sustain the highly valued Iowa livestock industry, which is a key part of the state economy. The report's recommendations were generated to provide guidance to the DNR and the Environmental Protection Commission, the group that oversees the DNR. The study group hopes the report will provide a sound basis for developing appropriate action by state officials that promote confidence in agricultural production and quality of life in rural Iowa.
What are the recommendations?
- Air-quality standards should be developed to regulate concentrations of hydrogen sulfide and ammonia. The study group suggested standards for specific levels of hydrogen sulfide and ammonia concentrations at both the property line and at a residence or public use area. The team offered two opinions on odor regulations. One stated that specific regulations should be developed. The other stated that before regulations can be set, more data must be gathered on odor concentrations and their potential link to reported health effects.
- The study group outlined policy strategies to help improve the siting of future confinement facilities.
- A number of technologies and management methods currently are available to control emissions. The study group outlined technologies related to housing ventilation, manure storage, and manure applications to land. ISU has conducted research and demonstrations on many of the technologies, some of which have shown dramatic results. There is a particularly strong case to be made on reducing odors through appropriate land-application methods, for example, incorporation of manure within 1 hour of application.
Photo: Aerator on lagoon
In making its recommendations, the study group was asked to review scientific evidence of human disease related to CAFOs. Although stating that no specific diseases among community residents can be linked to air emissions from CAFOs, the report outlined some evidence that suggests emissions may constitute a public health hazard, and that precautions should be taken to minimize exposures from CAFOs.
Beginning last summer, ISU's College of Agriculture and UI's College of Public Health assembled the study group of faculty to begin a comprehensive review of scientific information on CAFO issues. The study group consisted of 27 scientists who represented many disciplines, including animal science, veterinary medicine, agricultural engineering, environmental health, civil and environmental engineering, sociology, and economics. Before it was submitted to the DNR, the team's report was reviewed by independent national and international scientists. After release of the report, producers posed a series of questions. Examples of questions ask include the following:
Q. Does the report imply local control for siting CAFOs?
A. No. The study group recommends guidelines be developed based on siting and spatial planning considerations to include local physical factors and weather conditions.
Q. How practical will it be for farmers to notify IDNR before applying manure?
A. The study group agreed most farmers already practice a "good neighbor" policy before applying manure. Notification of DNR was recommended for those situations when farmers would anticipate exceeding hydrogen sulfide and ammonia concentration standards proposed by the study group. Furthermore, exceedance allowances and notification are part of the process that is appropriately addressed by state officials and rule-makers.
Q. How effective are the proposed available technologies for reducing air emissions?
A. ISU scientists have studied a series of alternative technologies and management practices for reducing air emissions from housing units, storage units, and land application. Results of these studies suggest that emissions can be reduced from 50 to 90 percent, depending on the specific strategy implemented.
The study group's 10-chapter report, including the executive summary, is available at www.extension.iastate.edu/airquality/
For a printed publication,
call (319) 335-9647 or send an e-mail to debra-venzke@uiowa.edu
