Ag & Energy - Lesson 17 - Ethanol and the Environment
Target Grade Level / Age Range:
High School: 9-12
As a result of this lesson, the student will …
- Describe how ethanol promotes a cleaner environment.
- Identify the effects ethanol has on emission levels of other pollutants.
- Discuss the negative effects of biofuels on the environment.
- Writing surface
- Blank paper- one per student
- Butcher paper- six large pieces
- Colored pencils/markers
Suggested Companion Resources
- Clean Air Act of 1990 - The amendments made sweeping changes to the way air quality is regulated in the United States
- Hydrocarbons (HCs) - formed from products made from crude oil
- Ozone - formed in the air when hydrocarbons and nitrogen oxides react in the presence of sunlight
- Aldehyde - emissions from the combustion of ethanol blends are slightly higher than when burning gasoline alone
- Carbon monoxide (CO) - a poisonous gas formed by incomplete combustion. It is readily produced from burning petroleum fuels which contain no oxygen in their molecular structure
- Carbon dioxide (CO2) - a normal non-toxic product of burning fuel, but it contributes to the greenhouse effect (global warming)
- Nitrogen oxides (NOx) - produced when high combustion temperatures exist
Background – Agricultural Connections
In 1990, the federal government passed amendments to the Clean Air Act . The amendments set minimum standards for air quality in America’s cities. These amendments also included provisions that required the use of oxygenated fuels in areas where excessive amounts of carbon monoxide (CO) existed. Since the majority of air pollution is caused by vehicle exhaust, using cleaner burning fuels is one alternative that provides nearly immediate results.
Interest Approach or Motivator
Begin class by having a brief discussion about the importance of having clean air. Ask students to draw why they think it is important to have clean air, and then allow them to share their drawings with the class. As the students are drawing, check their progress and provide them ideas of what could be drawn. When time is up or students are finished, have them share their drawing with someone sitting next to them. After that, ask for three or four students to share their drawings with the entire class. Again, allow three or four students to share their drawing with the entire class. Be sure to ask them why they think it is important to have clean air.
After they have shared, show the overview of the Clean Air Act of 1990. Have them read the overview and then discuss what the act mandates.
Clean Air Act of 1990
On November 15, 1990, Congress enacted the Clean Air Act Amendments. The amendments made sweeping changes to the way air quality is regulated in the United States. The legislation was designed to curb three major threats to human health and the environment: acid rain, urban air pollution and toxic air emissions.
Clean Air Act Highlights:
- Classifying nonattainment areas according to the extent to which they exceed the standard, tailoring deadlines, planning and controls to each area’s status.
- Tighten auto and other mobile source emission standards.
- Requires reformulated and alternative fuels in the most polluted areas.
- Revise the air toxics section, establishing a new program of technology-based standards and addressing the problem of sudden, catastrophic releases of toxics.
- Establishment of an acid rain control program, with a marketable allowance scheme to provide flexibility in implementation.
- Require a state-run permit program for the operation of major sources of air pollutants.
- Implement the Montreal Protocol to phase out most ozone -depleting chemicals.
The control of ozone based on regulating emissions of VOCs and NOx.
Since passage of the Clean Air Act of 1990 , ethanol has emerged as a possible solution for keeping our air cleaner. It is also important to know that ethanol-blended gasoline is one oxygenated fuel being offered as a solution.
Today, we are going to explore the benefits of ethanol and how its usage can improve our environment.
OBJECTIVE 1. Describe how ethanol promotes a cleaner environment.
- Ethanol is one of the best tools to fight air pollution.
- Ethanol is a clean burning, renewable fuel. E85 is the cleanest burning fuel available on the market today.
- Ethanol contains 35 percent oxygen.
- Ethanol is present in low levels in the environment; it is a natural product that results in the fermentation of plants.
- Ethanol used in gasoline has tremendous potential for a net reduction in atmospheric carbon dioxide levels.
- Ethanol is biodegradable, meaning it won’t harm groundwater in the event of a spill. Therefore, no water guidelines have been established for ethanol.
The American Lung Association of Metropolitan Chicago credits ethanol blended fuel with reducing smog-forming emissions by 25 percent since 1990.
After the students have written the information in their notes, ensure that students have a solid understanding of the information presented (how ethanol promotes a cleaner environment).
Ask students: What pictures or icons will help you remember the component concepts of this information? Brainstorm. Generate a bank of ideas on the board or overhead. Have students create representations. Using scratch paper divided into six squares, students will draw a “hieroglyphic” that helps them each of the benefits of ethanol. Share. After a specified amount of time, have students compare with one another and explain their creations.
Give students approximately four minutes to draw one icon for each of the six ways that ethanol promotes a cleaner environment. Draw the icon beside the statements in your notes. When students have finished, give them about 30 seconds to share their icons with a neighbor.
OBJECTIVE 2. Identify the effects ethanol has on emission levels of other pollutants.
- Ethanol results in reductions in every pollutant regulated by the Environmental Protection Agency.
- Hydrocarbons (HCs)
- Carbon monoxide (CO)
- Carbon dioxide (CO2)
- Nitrogen oxides (NOx)
Ethanol can help reduce these pollutants, but how? And what exactly are the impacts of these pollutants? Let’s examine this further.
For the next activity, the students will be divided into six groups. Each group will be assigned one of the pollutants. Distribute the information of each pollutant – one to each group. The group will become experts on their assigned pollutant. They can use the internet to find additional information if internet access is available. Once they are experts, they will teach their classmates the information about the pollutant they have been assigned. Provide each group with a large piece of butcher paper and access to markers so each group can make a poster to help teach the content. Encourage them to make sure they are getting the most important information. Once the posters have been created, each group will share their information with the class. Before giving the directions, place the students into six groups.
As students are working on this activity, be available to answer their questions. Monitor their progress and provide benchmarks for how much time is remaining. When time is up or when all groups are finished, have each group share their poster with the class.
- Hydrocarbons (HCs) are formed from products made from crude oil. Petroleum and gasoline consist of blends of more than 250 diverse hydrocarbons . Many of these are toxic; some, such as benzene, are carcinogens (cancer causing agents). Hydrocarbons escape into the air when refilling the gas tank, from the gas tank and carburetor during normal operation, and from engine exhaust. Hydrocarbons that evaporate from gasoline are sometimes called volatile organic compounds (VOCs). If uncontrolled, transportation sources would make up 30-50 percent of the total hydrocarbon emissions in the atmosphere. The automotive industry has developed and is using various vehicle emission control systems that control hydrocarbon emissions. Hydrocarbons also contribute to the formation of ground level ozone . Since ethanol is an alcohol, it does not produce hydrocarbons when being burned or during evaporation.
- Ozone, sometimes referred to as photochemical smog, is formed in the air when hydrocarbons and nitrogen oxides react in the presence of sunlight. It is more of a concern on warm, quiet, summer-like days when smog fills the air, creating a brownish haze in the lower atmosphere. This ground level ozone causes human respiratory stress and can cause plant damage, sometimes reducing crop yields. This ground level ozone does not increase the ozone that is in the stratosphere and does not block the sun’s harmful ultraviolet rays. Several U.S.- based studies conclude that, overall, the ozone forming potential of ethanol blends, which vaporize at lower temperatures due to higher volatility, is about the same as gasoline. In Canada, however, the volatility of ethanol blends must match normal gasoline.
- Aldehyde emissions from the combustion of ethanol blends are slightly higher than when burning gasoline alone. The concentrations are extremely small and are sufficiently reduced by the vehicle’s three-way catalytic converter found on all recent cars. The Royal Society of Canada termed the possibility of negative health effects caused by aldehyde emissions from the use of ethanol blends as being “remote.”
- Carbon monoxide (CO) is a poisonous gas formed by incomplete combustion. It is readily produced from burning petroleum fuels which contain no oxygen in their molecular structure. It is especially produced when excessive fuel-to-air mixtures are delivered and burned in the engine. More fuel and less air are necessary to start a cold engine and to keep it running until reaching normal operating temperature. Vehicles operating at colder temperatures (in winter months, during engine warm up, or in stop-and-go traffic) produce significant quantities of this toxic gas. By adding ethanol, which contains oxygen, combustion in the engine is more complete and CO is reduced. Research shows that reductions may reach as high as 30 percent depending on the type and age of the automobile, the emission system used, and the atmospheric conditions. Because of health concerns over carbon monoxide, the 1990 amendments to the Clean Air Act mandate the use of oxygenated fuels in many major urban areas (CO non-attainment areas) during the winter months.
- Carbon dioxide (CO2) is a normal non-toxic product of burning fuel, but it contributes to the greenhouse effect (global warming). All petroleum-based fuels cause increased atmospheric carbon dioxide levels. Using renewable fuels, such as ethanol, does not increase atmospheric carbon dioxide levels. The carbon dioxide formed during combustion is balanced by that absorbed during the annual growth of plants used to produce ethanol. Plants “breathe” carbon dioxide and give off oxygen. Therefore, increased use of renewable fuels made from plants will partially offset the global warming effect of burning gasoline. It is also worth noting that renewable fuel technology can result in a net reduction in atmospheric carbon dioxide levels. This is accomplished by transforming carbon dioxide into organic matter that is returned to the soil, thereby increasing soil fertility and reducing erosion. Ethanol use in gasoline has tremendous potential for a net reduction in atmospheric carbon dioxide levels.
- Nitrogen oxides (NOx) are produced when high combustion temperatures exist. NOx contributes to ground level ozone (photochemical smog). Several components of gasoline that impact NOx emissions, including olefins and aromatics, are reduced by adding ethanol to gasoline. EPA studies indicate the use of ethanol blends may slightly increase NOx emissions under some conditions, but the extent and effects are uncertain.
Make sure each group shares their poster and answer any questions that might arise.
Objective 3. Discuss the negative effects of biofuels on the environment.
- Ethanol production can have negative effects.
- It can decrease biodiversity through the deforestation of forests the clearing of grassland and wetlands.
- Changes in the carbon content of soils and carbon stocks of forests/peat lands could offset some of the benefits of greenhouse gas reductions.
- It can increase global warming because of a decrease in biodiversity.
- In high concentration, ethanol may cause biota, or the killing of living bacteria.
After students have written the information in their notes, review how ethanol production can have a negative impact on the environment by having them create a song.
- List key points. Instruct students to list the key words and phrases from the negative effects of ethanol production. As they write their information, create your list on the board or overhead. Students should check their lists with yours.
- Create a song. Tell students that they are to rewrite the words of a song they know using the words from their list. Note: You may want to share an example as a model. If your students are new to the Karaoke Moment, consider providing the lyrics of a simple song for them and allow them to work in small groups. Simple songs include: “Twinkle, Twinkle Little Star,” “Three Blind Mice,” “Row, Row, Row Your Boat,” “Take Me Out to the Ball Game,” “Mary Had a Little Lamb,” “The Ants Go Marching,” “Whistle While You Work,” or other songs your students know by heart.
- Share. After a designated amount of time, invite each group to share their new version of the song. Note: Time varies according to the amount of content expected in the lyrics. For songs like the ones listed above, allow 10-15 minutes.
Allow students to share their words or phrases. As they do, write them on the board and add information they might have missed. Using those words and phrases, rewrite the words of a common song. Share an example with your students that you have pre-made. Divide students into groups of three to rewrite their song. We will have eight minutes to complete this task. Once all groups have finished, we will take volunteers to share with the class.
As students are working, be available to provide assistance if they need it. This could be challenging, so make sure you have plenty of examples ready to help them. Once time is up or all groups have finished, ask for a few volunteers to share their song with the class.
To review the lesson have students draft a letter to themselves answering three questions.
- Pose three questions. Ask the students to write the following three questions in their notebook: What do you know the risks or benefits of ethanol production? What do you think you understand? What don’t you understand? Note: You may want to introduce students to the questions one at a time to focus their thinking.
- Students write letters to themselves. Students compose a letter to themselves (Descartes was a writer as well as a philosopher) explaining what they know, what they think they know and what they don’t understand about the topic. Allow about one to three minutes for thinking and writing on each question. You may want to have students share aloud after the first two questions to stimulate other students’ thinking.
- Collect the letters. The information is valuable for your lesson planning and assessment.
Give students 5 to 6 minutes to complete their letters. Monitor the students time and give them warning to help them pace their time before the end of the class period.
Answers to Assessment:
- Carbon monoxide
- Carbon dioxide
- Nitrogen Oxides
Ethanol and other oxygenates take the place of some of the gasoline and add oxygen to the combustion process which reduces levels of all pollutants controlled by the EPA.
- Carbon dioxide
Essential Files (maps, charts, pictures, or documents)
Did you know? (Ag facts)
- On November 15, 1990, Congress enacted the Clean Air Act Amendments. The amendments made sweeping changes to the way air quality is regulated in the United States. The legislation was designed to curb three major threats to human health and the environment: acid rain, urban air pollution and toxic air emissions.
- Have students brainstorm new mandates to include in a new Clean Air Act and then write a draft of the policy proposal.
- Have students develop a presentation about the risks and benefits of ethanol production.
- Arrange a tour of a local corn farm and discuss the impacts that ethanol production has on their farming operation.
- Adapted from Renewable Fuels Instructional Materials: Copyright © 2009 by National FFA Organization. Used by permission.
- E-Moments® is a registered trademark of the National FFA Organization. Copyright © 2004 by National FFA Organization. Used by permission.
- New materials, updates and revisions were funded in part by a grant from the Iowa Energy Center as a special project of the Iowa Agriculture Literacy Foundation.
Iowa Agriculture Literacy Foundation
Agriculture Literacy Outcomes
- Theme 1: Agriculture and the Environment
- Evaluate the potential impacts of climate change on agriculture
- Evaluate the various definitions of “sustainable agriculture,” considering population growth, carbon footprint, environmental systems, land and water resources, and economics
Education Content Standards
- HS-ESS3-1. Construct an explanation based on evidence for how the availability of natural resources, occurrence of natural hazards, and changes in climate have influenced human activity.
- HS-ESS3-4. Evaluate or refine a technological solution that reduces impacts of human activities on natural systems.*
Common Core Connections
- NSS-G.K-12.5. Environment and Society.
- NT.K-12.2. Social, Ethical and Human Issues.
- W.9–10.4 Produce clear and coherent writing in which the development, organization, and style are appropriate to task, purpose, and audience.
- W.9–10.2 Write informative/explanatory texts to examine and convey complex ideas, concepts, and information clearly and accurately through the effective selection, organization, and analysis of content.
- W.9–10.3 Write narratives to develop real or imagined experiences or events using effective technique, well–chosen details, and well–structured event sequences.
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