10 Iowa’s Pollution
Iowa’s Pollution by Megan Kane
CAFOs
Air pollution is defined as the release of contaminants into the atmosphere that pose risks to both human health and the environment. Because clean air is directly linked to overall well-being, air pollution remains a pressing concern for states and countries worldwide. These contaminants and the severity of them vary depending on the state. For example, one of California’s biggest pollutants is PM2.5, which is directly released when fuels including wood, oil, diesel, and gasoline burn. Other states such as New York have an increase in Ozone pollution. When it comes to the ranking of states and their air pollution, Iowa is considered fairly in the middle with an air quality index of 37.2. Iowa’s biggest contributor to their air quality is the bi products of concentrated animal feeding operations. These operations can produce biproducts such as ammonia, methane, particulate matter, endotoxins, nitrate, and hydrogen sulfide. All of these products produce health risks for those who come into contact.
Concentrated animal feeding operations (CAFOs) are high density farming operations designed to maximize production efficiency by housing large numbers of animals in confined spaces (Environmental Protection Agency). The operations unlike free-range farms, which allow animals to roam and graze, concentrated animal feeding operations operate under controlled environments to produce commercial agriculture at an accelerated rate to increase output and profitability. These operations start out as AFOs (Animal feeding operations) and then can become classified as CAFOSs once they meet certain criteria. To be an AFO these certain conditions need to be met: “animals have been, are, or will be stabled or confined and fed or maintained for a total of 45 days or more in any 12-month period” and “crops, vegetation, forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility” (Environmental Protection Agency). Once an AFO reaches a certain size and environmental impact threshold, it is classified as a CAFO. Although CAFOs serve a critical role in mass production of food, they also raise concerns regarding animal welfare, environmental sustainability, public health risks, and air quality.
Iowa’s biggest contributor to air pollution is the concentrated animal feeding operations. With over 3,000 CAFOs each housing over 1000 animal units each, these operations contribute an abundant amount to the health in Iowa. These operations create emissions that affect air quality and public health throughout the state. Iowa has a variety of CAFOs, including beef, dairy, poultry, and swine operations, but swine production dominates within Iowa as the most abundant CAFO. These operations generate biproducts that contribute to air pollution and public health, some of which include ammonia, methane, particulate matter, endotoxins, nitrate, and hydrogen sulfide. Nearly 40% of Iowa’s air pollution, greenhouse gases, and methane emissions are contributed from CAFOs. Ammonia and hydrogen sulfide are both products of the decomposition of animal waste produced by these operations. Livestock in Iowa produced on average 68 billion pounds of manure a year. With the number of CAFOs continuing to increase within the state the waste produced, and gases emitted into the atmosphere continue to worsen. Long term production of these biproducts can pose a threat to the quality of life for both humans and animals throughout Iowa.
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Top Emissions
Ammonia
Ammonia is a compound made of nitrogen and hydrogen. This compound is essential in the production of most plants and agriculture, contributing to plant growth. It is naturally produced through processes such as decomposition of organic matter, nitrogen fixation, and animal waste breakdown (Enviroliteracy Team). Ammonia is a key component in health fertilizers and promoting healthy crops. However, excess ammonia could cause health problems and concerns for the environment depending on the population’s level of exposure. Balancing ammonia levels is important to productive agricultural benefits while minimizing pollution harm.
A natural source of ammonia is produced through decomposition of organic matter. The process known as ammonification is when bacteria/fungi break down animal waste, or plants and animals when they die. This form or recycling converts dead organic material into usable nutrients for the soil and the environment. This process can happen in different places such as soils, aquatic ecosystems, and compost piles. In Iowa we see an abundant amount of our ammonia production in compost piles due to the large animal population we see in Iowa. The decomposition of animals creates an accelerated version of the natural ammonification process.
Another natural source of Ammonia can be found and produced through nitrogen fixation. This is when atmospheric nitrogen gas is converted into ammonia. There is a large amount of nitrogen gas already in our atmosphere (78%) but it is chemically inactive and unavailable to most. Certain bacteria can make nitrogen biologically accessible; these include rhizobia, free-living nitrogen-fixing bacteria and cyanobacteria. Rhizobia is a symbiotic bacteria found in root nodules, where they convert nitrogen into ammonia, enriching the soil with nutrients. Free living nitrogen fixing bacteria is an independent bacterium that does not need a host plant to contribute to nitrogen accessibility. Cyanobacteria is a microorganism that engages in photosynthesis along with fixing nitrogen. Nitrogen fixing is essential for ecosystem stability; it enables plants to absorb nitrogen through ammonia.
The biggest producer of ammonia within Iowa is through animal waste. Natural animal byproducts such as urine and feces provide an abundant amount of ammonia to the environment. The way this happens is through what animals consume. Animals eat protein which has nitrogen in it. This protein is metabolized, and excess nitrogen is excreted through urea or uric acid. Bacteria in the environment then break down these compounds releasing ammonia. This process of the ammonification of animal waste can be found naturally in ecosystems and is used to fertilize soils for more growth. However, in Iowa we see an excess amount of these emissions because of the average 68 billion pounds of manure produced a year. Manure management is essential to maintain and limit these emissions that occur.
The over production of ammonia could have negative health effects on the environment and health of the population. Even long exposure to low concentrations of ammonia can have a negative effect. Ammonia itself can cause irritation to the eyes, nose, and throat, headaches, nausea, diarrhea, cough, chest tightness, nasal congestion, palpitations, and alterations in mood (Science Direct). These side effects can start occuring at concentrations as low as 5 ppm but become very noticeable around 30 ppm. In most areas levels as high as 30 are uncommon but for those with constant low exposure due to agriculture proximity these symptoms are more likely to occur at lower concentration levels. Ammonia is also a main contributor to PM2.5 (particulate matter) production. PM2.5 is defined by the World Health Organization (2013) as particles of air pollution that are small enough to penetrate the thoracic region of the respiratory system once inhaled (Science Direct). Exposure to PM2.5 can lead to respiratory problems such as asthma or more serious illness in extreme cases.
A study conducted by Malley et al. addressed premature mortality as a result of exposure to PM2.5 resulting from agriculture emissions in 2019. Adults 30 years of age were examined for COPD, IHD, ischemic stroke, LC and Type 2 diabetes. Children less than 5 were assessed for lower respiratory infections. The study determined that the health burden, premature deaths, due to PM2.5 as a result from agriculture was 537 thousand deaths. Out of these deaths 9% were a direct result from contribution of ammonia to PM2.5 formation. Overall, the study found that the more ammonia emitted results in more particulate matter being formed, this all contributes vastly to the respiratory health of our population.
Hydrogen Sulfide
Hydrogen sulfide (H2S) is emitted through livestock production but not usually included in sulfur emission estimates (Nature). Emissions of hydrogen sulfide contribute to the creation of secondary aerosols through oxidation and conversion to aerosol sulfate. Along with this hydrogen sulfide is one of the most common hazardous substances related to poisoning deaths in occupational settings (National Library of Medicine). In Iowa the compound is created through agriculture methods and farming production. Hydrogen sulfide is a natural product of anaerobic decomposition of organic material in livestock manure storage systems (Pork Gateway). This gas poses an environmental issue and affects air quality if overly produced.
The production of hydrogen sulfide through the decomposition of manure can vary depending on conditions such as, temperature, pit area volume, and daily sulfur intake. A study by Arogo et al. also found that settled manure has distinct layers that are each unique in their production of sulfide. The top three layers contribute the highest amount of sulfide when going through anaerobic conditions (Pork Gateway). H2S production increases drastically inside animal buildings such as CAFOs and starts being released when manure agitation starts. A study was conducted to compare the producers of hydrogen sulfide and see how much they impact production rate. Animal feeding operations were the most commonly studied source during this study and maintained among the highest concentration measurements. However, they didn’t always contribute the most biproduct to the air quality. This is mainly because a lot of animal feeding operations are enclosed, accumulating more H2S rather than emitting it (Nation Library of Medicine). Although this still poses a threat to the air quality within Iowa, it poses a bigger threat to farm workers’ air quality at work.
Given Iowa’s large amount of concentrated animal feeding operations, the production and release of hydrogen sulfide pose a significant concern for both environmental and public health in parts of the state. The animal operations already produce strong odors due to the high density of livestock in such a confined space, but hydrogen sulfide adds another layer of intense odor, often described as similar to rotten eggs. This pungent smell makes the gas easily identifiable, making its presence known to workers and residents living in proximity to these operations. Hydrogen Sulfide is known for its hazardous chemical properties. It Is highly corrosive, capable of deteriorating metal surfaces and infrastructure over time. Additionally, the gas is flammable and explosive meaning it poses a serious health threat in confined spaces. Exposure to hydrogen sulfide and lead to serious health effects, especially when there has been prolonged or repeated exposure. Some of the mild symptoms include irritation of the eyes and respiratory system, which lead to coughing and difficulty breathing. When exposure is prolonged or continuous you can experience symptoms such as a decline in motor function and other symptoms linked to neurological impairments. As concentrated animal feeding operations continue to expand in Iowa, hydrogen sulfide emissions continue to impact air quality and public health remains an urgent concern.
Greenhouse Gases
Greenhouse gases are critical factors in climate change and air quality, as they trap heat in the atmosphere and contribute to the progressive warming of the Earth. These gases form a thermal blanket around the planet disrupting climate patterns, temperatures, and weather events. The most abundant greenhouse gas emitted is carbon dioxide. Carbon Dioxide is emitted through burning fossil fuels, solid waste, trees, and other biological materials. Methane is another greenhouse gas, emitted through production and transport of coal, natural gas, and oil; along with some emissions resulting from livestock, solid waste landfills, and agricultural processes. Nitrous Oxide is emitted through agricultural, land use, and industrial activities. Fluorinated gases, including hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride, and nitrogen trifluoride, are produced through household, commercial, and industrial applications. Fluorinated gases are typically produced in smaller amounts but still have global warming potentials ranging within the thousands to tens of thousands (Environmental Protection Agency).
Carbon Dioxide
Carbon Dioxide being the most emitted gas is normal for most states due to its primary emission being through human activities. “In 2022, carbon dioxide accounted for 80% of all U.S. greenhouse gas emissions from human activities” (Environmental Protection Agency). The main contributors of this being transportation, electricity, and industry. Transportation causes the combustion of fossil fuels, gasoline and diesel, when transporting people and goods. Given that electricity is such an important resource throughout the United States to power homes, businesses, etc. the amount of carbon dioxide emitted through the combustion of fossil fuels used to generate electricity accounted for 30% of the total US carbon dioxide emissions. Industries also use industrial processes that use fossil fuel consumption emitting carbon dioxide into the atmosphere. (Environmental Protection Agency).
Reducing fossil fuel consumption is a crucial step in mitigating air quality and decreasing reliance on non-renewable energy sources. There are several strategies that can be implemented to minimize carbon emissions and promote a more sustainable energy future. One of the most common ones that has been making headway is switching fuel. This can involve transitioning away from fossil fuels toward renewable alternatives such as solar, wind, hydroelectric, and geothermal energy. Some other strategies would be implementing more energy efficiency and energy conservation. Energy efficiency refers to utilizing advanced technologies and optimized systems to get the same output while consuming less energy. On a larger scale, industrial sectors can implement process optimization, waste heat recovery, and smart grid systems to optimize efficiency and reduce unnecessary fuel use. Energy conservation, on the other hand, involves behavioral changes that help reduce overall demand for fossil fuel consumption. By integrating these strategies-fuel switching, energy efficiency improvements, and energy conservation efforts- communities and industries can make significant strides toward reducing carbon emissions.
Nitrous Oxide
Nitrous Oxide is a colorless gas with a slightly sweet odor, commonly known as laughing gas due to its historical use as an anesthetic in medicine. Although nitrous oxide is naturally present in the atmosphere, human activities have significantly increased its concentration, making it a notable contributor to global greenhouse gas emissions and climate change. The main productions of this gas include agriculture, fuel combustion, wastewater management, and industrial processes. Nitrous oxide is naturally present in the atmosphere but has created abundance through these human activities. In fact, “40% of total nitrous oxide emissions come from human activities” (Environmental Protection Agency). Among human-related sources, agriculture and land use are the most prominent contributors, with agricultural soil management alone accounting for a staggering 75% of global nitrous oxide emissions. The excess production occurs due to fertilizer application, manure storage, and microbial activity in the soil. As well, manure decomposition in livestock operation releases significant amounts of nitrous oxide, especially under poor waste management conditions. Other than agriculture, fuel combustion from transportation and industrial operations releases additional nitrous oxide, exacerbating air pollution and environmental degradation. Furthermore, wastewater treatment plants can contribute to nitrous oxide emissions as organic matter decomposes in oxygen-limited conditions.
There are multiple strategies to reduce nitrous oxide emissions, which play a significant role in atmospheric pollution and climate change. Within agriculture, a key approach is limiting the use of nitrogen-based fertilizers, as excessive application leads to nitrous oxide release through soil microbial processes. By adopting precision fertilization techniques and incorporating alternative nutrient management strategies, farmers can significantly decrease emissions while maintaining soil fertility. Nitrous oxide is also admitted through fuel combustion, making vehicle efficiency an important reduction method. Encouraging the transition to electric and hybrid vehicles, along with improved emission regulations, will help improve pollution levels. By integrating these strategies over time nitrous oxide levels will lower, therefore improving air quality. (Environmental Protection Agency)
Methane Emissions
Methane is a colorless, odorless gas that is released through both natural processes an human activities, making it a significant contributor to global greenhouse gas emissions and 17% of Iowa’s greenhouse emissions. Several human activities contribute to methane emissions, with natural gas leaks and livestock farming being two major sources. Agriculturally, animals such as cattle, swine, sheep, and goats naturally produce methane during the digestive process. Along with this methane is also produced during the storing and handling methods of manure. The second largest source of methane is natural gas and petroleum systems. This means that methane is emitted into the atmosphere during the production, storage, distribution, and use of natural gas, along with the transportation refinement and production of crude oil (Environmental Protection Agency). Addressing methane emissions is essential for minimizing environmental impacts and creating sustainable long-term solutions for global climate stability.
The Environmental Protection Agency offers a variety of resources aimed at reducing methane emissions, which is an essential step in improving air quality and minimizing climate change. One of the initiatives is the Globa Methane Initiative, which promotes global methane reduction strategies through international partnership. There are several specific strategies that industries and agricultural operations can implement to reduce methane emissions effectively. One such method is frequent upgrading and maintenance of equipment used in industrial processes. The inability to frequently upgrade this equipment can lead to gas leaks, which contribute a significant amount of methane emissions into the atmosphere. Another strategy would be to alter manure management strategies to help reduce the emissions from animal biproduct. To combat the methane produced through anaerobic decomposition farms can apply manure handling techniques such as anaerobic digester, which capture methane for energy use. The environmental protection agency’s ongoing initiatives and international cooperation ensure that global methane reduction efforts remain a priority, leading to a healthier atmosphere.
Fluorinated Gases
Fluorinated gases are unlike other greenhouse gases because they do not have a natural source that emits them into the atmosphere. They are produced almost directly and entirely from human-activities. Along with this, these gases have much higher global warming potentials compared to the other greenhouse gases. This means even the smallest concentrations of these gases can have big effects. Hydrofluorocarbons, a main category of fluorinated gases, could be used as refrigerants, aerosol propellants, foam blowing agents, etc. The use of refrigerants is the main source of emissions. These substitutions for ozone-depleting substances make up 90% of all fluorinated gas emissions. Along with this, the manufacturing process emits an abundant amount of HFCs into the atmosphere as well through things such as leaks, servicing, and disposal of equipment.
Fluorinated gases are known for their long atmospheric lifetime, meaning that once released they remain in the environment for years, sometimes decades before the concentration of the gas begins to decline. There are strategies that will help reduce emissions even if we don’t see it right away. An example of these strategies is to reduce and enact better handling of refrigerants that emit fluorinated gases. Improving the management and handling of refrigerants is the first step in improving emissions. Industries can put into play fluorinated gas capture and destruction processes to reduce the emissions being added to the atmosphere. These processes break down harmful gases before they can get into the environment by using chemical treatments and advanced filtration methods. Although the benefits of these strategies may not be immediately visible, early intervention and consistent implementation will help reduce long-term environmental impacts and slow the accumulation of fluorinated gases in the atmosphere.
Policies that are Already in Play
All this being said, Iowa does have some policies already in play to help their residents with air pollution and quality. One of which is the Clean Air Act which calls for state, local, and federal governments to implement the revisions to help reduce pollution. The main goal of the Clean Air Act is to implement amendments and revisions that will control some common air pollutants. EPA is required to establish national ambient air quality standards that states then use to develop their individual implementation plans. The act also enforces states to control pollutants that drift over state lines and into other regions. When it comes to more toxic pollutants the EPA issues national limits. The states have the option of adopting a program through the EPAs authority that will enforce toxic emission standards, or they can create their own plan. States however cannot have a more strict or enforceable plan than is required by the EPA. The Clean Air Act also has plans in place for more specific or less common pollutants such as acid rain, ozone layer protection, and regional haze (Environmental Protection Agency).
Another policy in play throughout Iowa and the rest of the country is the federally mandated Pollution Prevention Act of 1990. The act focuses on source reduction and prevention of pollution before it occurs. Congress found that the opportunities for source reduction of pollution within the U.S is abundant and just not taken advantage of. A source reduction program is the first step EPA took in preventing pollution, this program collects and disseminates information and provides financial assistance to States. The act also provides grants to states to help promote the use of the source reduction techniques throughout businesses and other organizations within the States. For pollutants that don’t have an available source reduction method, or one did not describe within the Pollution Prevention Act, the policy states that they should implement recycling in an environmentally safe manner. Overall, the policy aims to reduce pollution at the source of the emission rather than try to correct something that has already been done.
Overall Iowa relies heavily on the Environmental Protection Agency and the Iowa Department of Natural Resources to help control and mandate the air pollution within the state. These organizations regulate about 188 air pollutants known throughout the state to cause serious health effects. The national ambient air quality standards and national emission standards for hazardous air pollutants are also used to help guide the state in prevention plans and policies. The National Ambient Air Quality standards is used to define maximum concentrations allowed of air pollutants and the amount that must be contained by industries throughout the state.
How to Get Involved in Iowa
The state of Iowa has resources available to those who want to get involved with the health of air quality within their community. Iowa’s air quality bureau recognizes the importance of public involvement and encourages citizens input, allowing individuals to voice concerns and stay informed about environmental policies. Through meetings, public feedback sessions, and workgroups, civilians can engage in meaningful discussions and help shape air quality initiatives that protect both public health and the environment.
One of the most direct ways to get involved is through the Environmental Protection Commission, which plays a crucial role in Iowa environmental oversight. This panel consists of nine citizens who are appointed by the governor and confirmed by a vote of the Senate. These individuals bring expertise from various backgrounds, ensuring a balanced approach to addressing Iowa’s environmental challenges. They have meetings and provide insight into Iowa environmental protection efforts and policies. The panel conducts open meetings every third Tuesday of the month, in the meetings citizens can ask questions, gain insight into ongoing protection efforts, and stay informed on policy changes that may not always be widely publicized. Those interested in learning more or attending meetings can find meeting schedules, minutes, and agendas on the official Environmental Protection Agency website. By taking an active role in these discussions, Iowans can help advocate for cleaner air, improved regulations, and stronger environmental protection that benefit both present and future generations.
Another valuable opportunity for citizens of Iowa to engage in environmental discussions is through the Client Contact Group, which serves as a platform for public involvement. This group is made to allow the public to learn about programs and requirements being fulfilled that relate to the environment. The client contact group is an open meeting used to discuss new and old programs or developments happening at the state and federal level. It serves as an accessible avenue for communication between government agencies and the communities they serve. These meetings are held virtually to make it easier for anyone in the state of Iowa to attend. These meetings are held the Tuesday prior to each month’s Environmental Protection Commission meetings. Minutes and agendas for these meetings can be found on the environmental protection agencies website. By engaging with the Client Contact Group, Iowa residents can take an active role in promoting environmental protection.
Resources:
Air Pollutants. (n.d.). Www.iowadnr.gov. https://www.iowadnr.gov/environmental-protection/air-quality/air-pollutants
HOTHI, H. (2024, December 3). Factory Farms Affecting Iowa. ArcGIS StoryMaps; Esri. https://storymaps.arcgis.com/stories/b94d3ee6b07e46de822c43cf5676e357
US EPA. (2015, August 24). Animal Feeding Operations (AFOs) | US EPA. US EPA. https://www.epa.gov/npdes/animal-feeding-operations-afos
Wyer, K. E., Kelleghan, D. B., Blanes-Vidal, V., Schauberger, G., & Curran, T. P. (2022). Ammonia emissions from agriculture and their contribution to fine particulate matter: A review of implications for human health. Journal of Environmental Management, 323(116285), 116285. https://doi.org/10.1016/j.jenvman.2022.116285
Malone Rubright, S. L., Pearce, L. L., & Peterson, J. (2017). Environmental Toxicology of Hydrogen Sulfide. Nitric Oxide : Biology and Chemistry, 71, 1–13. https://doi.org/10.1016/j.niox.2017.09.011
EWG. (n.d.). EWG Study and Mapping Show Big CAFOs in Iowa Up Fivefold Since 1990. Www.ewg.org. https://www.ewg.org/interactive-maps/2020-iowa-cafos/
Air Quality. (n.d.). Www.iowadnr.gov. https://www.iowadnr.gov/Environmental-Protection/Air-Quality
EPA. (2023). U.S. Environmental Protection Agency. US EPA. https://www.epa.gov/
Board, N. P. (2015, December 3). Hydrogen Sulfide Concentrations Around Swine Farms – Pork Information Gateway. Pork Information Gateway. https://porkgateway.org/resource/hydrogen-sulfide-concentrations-around-swine-farms/
Wyer, K. E., Kelleghan, D. B., Blanes-Vidal, V., Schauberger, G., & Curran, T. P. (2022). Ammonia emissions from agriculture and their contribution to fine particulate matter: A review of implications for human health. Journal of Environmental Management, 323(116285), 116285. https://doi.org/10.1016/j.jenvman.2022.116285
Team, E. (2025, April 29). What naturally produces ammonia? – The Environmental Literacy Council. The Environmental Literacy Council. https://enviroliteracy.org/animals/what-naturally-produces-ammonia/