AIR & THE
Activity 10 (Explain): What's Going On in Our Airshed?
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In this activity, students learn about the two major forms of nitrogen pollution in the Chesapeake Bay airshed: nitrate and ammonium. They interpret maps to understand how nitrate and ammonium pollution have changed over time, and they read about the two pollutants in order to compare and contrast them. Finally, students add to their Chesapeake Bay Pollution model and identify sources of nitrogen pollution in their communities.
Activity Objectives & Materials
Approximate Time: 45 minutes
Students will identify major sources of pollution in the airshed
Computer & projector
Sentence strips for Chesapeake Bay pollution model: nitrate, ammonium, power plants, agriculture, cars, trucks, etc.
Nitrogen Air Pollution
Map Sources: The maps for this activity come from the National Atmospheric Deposition Program/ National Trends Network.
DCI: LS2.C: Ecosystem Dynamics, Functioning, and Resilience
DCI: ESS3.C: Human Impacts on Earth Systems
SEP: Creating & Using Models
CCC: Cause & Effect
What kinds of things produce air pollution?
Possible student responses: cars and trucks, factories, power plants, fires
If students have completed other modules in On the Air, they will likely be familiar with these answers. If they are new to studying air pollution, they may be less familiar and will need a brief introduction. Either way, the point of this warmup is to focus students’ attention on specific sources of air pollution that affect the Chesapeake Bay.
1. Frame the Activity
Now that we have a model of how pollution can get into the Chesapeake Bay, we need to figure out the actual sources of that pollution if we’re going to do something about it. We know that the number one source of pollution is agriculture (farms). The second largest source of pollution to the Bay is air pollution. But where is that air pollution coming from? During our activity today, we’ll work on figuring that out.
2. Nitrate Air Pollution
Display the map below so all students can see it.
mind students that the blue shape represents the Chesapeake Bay airshed – the area that shares air with the Chesapeake Bay. Tell them that this map shows one kind of nitrogen pollution in the air called “nitrate”. Review the scale of the map with students (red is high, green is low), then ask them what they notice about the map. Key takeaways:
The nitrate level is very high in the northeast
The nitrate level is very high in the airshed
Point out to students that this map is from 1985, so the nitrate level was very high then. Tell students that in a few minutes they are going to read about nitrate in more detail.
Accessibility Note: The maps for this activity depend on students seeing different colors. If you have students who are colorblind, they may need assistance in interpreting the maps.
3. Ammonium Air Pollution
Display the map below so all students can see it:
Tell students that this map shows a different kind of nitrogen pollution in the air called “ammonium”. Ask students what they notice about this map. Key takeaways:
The ammonium level is higher in the middle of the country
The ammonium level is lower in the Chesapeake Bay airshed.
Based on these two maps, which type of air pollution (nitrate or ammonium) do they think is the bigger problem for the Chesapeake Bay?
Students will likely say nitrate, although remind them that this isn’t the end of the story (it’s only 1985).
4. Nitrate and Ammonia Air Pollution
Hand out the reading: “Sources of nitrogen air pollution”. As students read, they will identify key information about sources of nitrogen pollution, and fill in their Venn diagram.
After students have finished the reading and filled in their Venn diagrams, lead a discussion to clarify important information, mainly that nitrate comes from mainly from burning fossil fuels (in power plants and vehicles, and ammonia comes mainly from agriculture).
5. What's Going on With Nitrate?
Display the 1985 nitrate map for students to see. Ask them why they think the nitrate pollution was so bad in the Chesapeake Bay airshed in 1985. Use questions and discussion to help them recognize that there were a lot of power plants and a lot of transportation (cars and trucks) in this area at the time. Have students predict what has changed with nitrate since 1985. After they have made their predictions, click through the animated versions of the nitrate maps (download and use the right arrow to advance from map to map).
Were students’ predictions right? Ask students why they think the nitrate pollution went down so much. Use questions to help them realize that the power plants we use got cleaner and the most polluting ones closed. Cars also began to pollute less. Nitrate reduction is a success story, but we need to keep moving in the right direction.
6. What's Going on With Ammonium?
Display the 1985 ammonium map for students to see. Ask them why they think the ammonium level is worse in the middle of the country compared to the Chesapeake Bay airshed. Use questions and discussion to help them recognize that most of the country’s agriculture is in the Midwest. Have students predict what has changed with ammonium since 1985. After they have made their predictions, click through the animated versions of the ammonium maps (download and use the right arrow to advance from map to map).
Were students’ predictions right? Ask students why they think the ammonium pollution went up so much. Use questions to focus on the idea that increased fertilizer use is resulting in increased ammonium air pollution. While this has affected the Chesapeake Bay airshed less than other parts of the country, it is still going up. Right now, the amount of nitrate deposition and ammonium deposition in the Bay is about the same.
7. Improving Our Model
Ask students where nitrate and ammonium belong in their Chesapeake Bay pollution models. Have students add them to their models where appropriate to add detail to “nitrogen air pollution.” Also ask about sources of these pollutants. Where can agriculture (fertilizer, manure), power plants, cars & trucks, and any other sources students think are appropriate be added?
8. Formative Assessment
Ask students what they think is the largest source of nitrogen air pollution in their community? Why do you think so? What kind of air pollution does it produce?
Key things to look for: do students correctly match the air pollution to the kind of source, do they choose sources that are prevalent in their communities (ex. cars and trucks most likely, which contribute to the nitrate pollution)