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What's The Air Forecast?

Activity 6 (Explore): Air Quality in the

DC/Baltimore Region

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Activity Overview

Activity Summary

In this activity, students learn about what the Air Quality Index (AQI) is to better understand what a Code Red Day is. They use the Clean Air Partners website to research the history of air quality in the region to see patterns in how it has changed over time.

Activity Objectives & Materials

Approximate Time: 2 class periods (approx. 90-120 minutes)


  • Students will learn to interpret the Air Quality Index (AQI)

  • Students will research current and historical AQI data from the DC/ Baltimore area

  • Students will identify the major air pollutants in the DC/Baltimore area and analyze data to show how they have changed over time



  • Computer & projector

  • Student computers (highly recommended)

  • “The air quality today in <blank> is…” (see activity)


  • Air Quality Index reading (double-entry journal)

  • Historical AQI Data Investigation

  • AQI Through the Years

  • Graph paper (optional)

Standards Connection

DCI: ESS 3.C – Human Impacts on Earth’s Systems

SEP: Obtaining, Evaluating, and Communicating Information

CCC: Patterns



Look at the definition we created for air pollution earlier in this investigation. Based upon what we have learned so far, how would you define the term “air quality”?

  • After students have completed the warmup, have them share with a small group to come up with a common definition. Then have groups share out, and develop a common class definition of air quality. Put this definition up on the wall with the definition for air pollution, and revisit it as necessary in the module to add detail.

  • Sample definition: “How clean the air is based on how little air pollution there is”


1. Frame the Activity

Tell students that they now have a good understanding of what happened in Washington, D.C. on July 9, 2018. That day was called a Code Red Day. Ask students why they think it might have been called “Code Red”? They will likely say something like – because it is dangerous, and red is a color that means danger. Acknowledge their suggestions, but don’t tell them if they are right or not. Ask them if they think there have been other Code Red Days in the area. After they have a chance to respond, tell them that today they are going to learn about why that day was called a Code Red day, and they’ll learn about how air pollution in the area has changed over time.

Step 1

2. The Air Quality Index (AQI)

Connection to Module 1If you have done Module 1 with students, you may want to skip over the AQI portion of the activity, or use this time to review what students have already learned about the AQI.

Tell students that they are going to start by reading an article that explains what a Code Red Day is. Pass out the double-entry journal article “The Air Quality Index”. Review the directions, then have students read and complete the questions. Afterwards, review the answers to check for student understanding. In particular, make sure students understand why the day was called a Code Red Day.

Show students a color version of the scale (either printed out or projected) to review the different colors and what they mean, including the numbers and what you should do if the level of pollution on the index is reached.


3. Looking Up The Current AQI

Tell students that there are a lot of different ways to find out what the current air quality is in their neighborhood or around the world. Pass out student computers (if available) or project a web browser were all students can see. With students, go to the Clean Air Partners website for current and forecasted AQI: Click on “current” at the top right corner of the map to see the AQI color in different places in the area. Click on the point on the map closest to where the school is. The page will scroll to the bottom where there is specific AQI data. You can also switch pollutants to see how the AQI changes.

Current Air Quality.jpg
Current Air Quality - specific.jpg

If you have not already, put up the “The air quality today in <blank> is…” signs somewhere in the classroom (see box below). Choose a student to write in the AQI for the school location, including what the AQI is due to (ozone, PM, etc.). Next, have students go to the World Air Quality Index website: Students can use the map to find and click on another city to look up its AQI, or they scroll down and type a city into the search bar. As a class, choose a few more cities to look up the AQI for. Put these city names into your other signs, and have students put in the AQI information including what it is due to. Try to pick cities that are in different parts of the world and that have different AQIs. Every day at the beginning of class, have students look up the AQI in those cities to update the signs.


The Air Quality Today in <blank> isTo give students practice looking up the AQI, create a series of signs that say “The air quality today in <blank> is…<blank> due to <blank>” that students can change the numbers on (ex. with a taped-on notecard or using a dry erase board). Make one sign for the location of the school. Also have students choose cities they want to look up the AQI for each day (preferable cities around the world). Start each day by having students update the numbers on the sign and compare what it would be like to be a middle school student in different cities on that day.

Before moving on, share other ways that students can look up the AQI, for example using apps on their phones such as Clean Air Partners Air Quality app, and the Air Visual app. If students are allowed to use their smartphones at school, show them how they can add these apps to their phones to look up the AQI.

Step 4

4. Researching Historical AQI 

Remind students of when you asked them earlier about whether there have been other Code Red Days in the area besides July 9, 2018. Tell them that in this next part of the activity, they are going to find out. Pass out the AQI Data Investigation sheet, and tell students that they are going to research Code Red days from the past to look for patterns in how air pollution in the area has changed over time.

Read the directions at the top of the sheet with students to bring them back to the Clean Air Partners website where they can look at looking at the historical air quality data:

CAP Historical AQI page.jpg

Start by having all students look up the same date: July 20, 2017 is a good choice since it was a Code Red Day. Once students have navigated to the correct month, they can bring up the data from specific monitors for that date by clicking on the “details” for July 20:

CAP Historical AQI monitor data.jpg

Using this information, have students answer the questions on their handouts.

  • What was the AQI for this date? 151

  • What was the Particulate Matter (PM) AQI? 71

  • Where was the PM AQI the highest (what site name)? Millington

  • What was the Ozone AQI? 151

  • Where was the Ozone AQI the highest? Edgewood

  • Why was this a Code Red day in the area? Ozone over 150

After this example, have students go to 3 other dates that each have a different AQI color (green, yellow, and orange), and have them answer the questions on their handout for those dates. Note that going back in time will likely lead to worse pollution days, and the summer has worse pollution than other seasons. July 2017 has four different levels, so students can also stay on that month.


Once students are finished with the historical research, they can answer the questions at the bottom of the sheet. Review the answers when all students are finished:

  • Most poor air quality days in the DC/Baltimore region are caused by particulate Matter (PM 2.5) and Ozone (in fact, many sensors in the area only measure these two pollutants)

  • The pollutant which caused the Code Red Day on July 9, 2018 was ozone with an AQI of 166 in Beltsville, MD


Once students have finished with this part of the activity, you can collect their computers.


Timing Note: If you are doing this activity over the course of two (or more) days, this is a good point to break up the activity.

5. AQI Through the Years

Ask students if they think the air quality in the area has been getting better or worse since you were a kid. Listen for student responses (students generally think that it has gotten worse), then tell them that they are going to be looking at data to see if their predictions are right or not. Pass out the sheet “AQI Through the Years.” Have students read the top part of the sheet, and then review with them what information is shown (it is the July AQI calendars every 5 years 1995-2020).  Have students count and graph (optional) the number of days for each AQI level (color).

AQI through the years months.jpg

Teacher Tip: If students are working off of a black & white copy of the handout, it will be hard to count the number of days of each AQI (they can see the numbers, but they are small). It will help if you project a copy of the handout so students can more easily count the colors

AQI through the years image.jpg

Digging into the Data: There was only one Code Red day in July, 2020. Did you notice what day it was? The AQI was in the yellow or green for almost all locations except for two, where it was in the red for PM. What could have added PM to the air on this date?

A Note about Data Analysis & Math Integration: There are many ways to analyze these data. The most complex analysis would be to make a scatter plot for each color, then draw a line of best fit and determine the slope to see how the number of days of each color is changing over time. Depending on students’ grade level and current math ability this may be too advanced. You can also have students average the first three years for each color and the last three years and compare the averages to see how the number of days is changing in general. You can have students find the average of all the numbers for a particular color and then compare the numbers in 1995 and 2020 to the average. The point is, use whatever math skills your students have (or are working on) to look for a pattern in the way the numbers are changing. 

Data Analysis: There are two types of “Analysis” answers here based on two different analysis methods. Each method will still provide enough information to draw conclusions for the end of the activity.

Once they are finished counting/graphing, discuss with students how they can analyze patterns in these data (see note below for ideas). When you have decided on an option (or options) have students complete the analysis and answer the questions on the back of their sheet.


Basic analysis: How have the number of each of the days changed?

  • Green: stayed about the same

  • Yellow: went up a lot

  • Orange: went down a little

  • Red: went down

  • Purple: went down

Advanced Analysis: How have the number of each of the days changed?

  • Green

    • average of 1995-2005: 3

    • average of 2010-2020: 3.7

    • change: +0.7

  • Yellow

    • average of 1995-2005: 11.3

    • average of 2010-2020: 21

    • change: +9.7

  • Orange

    • average of 1995-2005: 7

    • average of 2010-2020: 3.3

    • change: -3.7

  • Red: went down

    • average of 1995-2005: 7

    • average of 2010-2020: 3

    • change: -4

  • Purple: went down

    • average of 1995-2005: 2.7

    • average of 2010-2020: 0

    • change: -2.7


When students are finished with their analysis, discuss what trends they see in the data. In other words, patterns of change are not always smooth (linear), but they may still go in one direction or another. For example, 2000 was a pretty good July for air quality, but it is more likely the exception than the rule. Make sure that students understand that overall, the air quality is getting better, but there can still be good or bad years for various reasons.

Research Sources: If you are using chart paper to make of list of research sources for the module, you can add the Clean Air Partners website and the World Air Quality Index website as sources of AQI data.

6. Reaching A Conclusion

After the discussion, have students answer the conclusion question using data from this activity.


Sample response: The amount of air pollution in the DC area in July has gone down since 1995. In 1995, there were 6 days in the purple range (very unhealthy), but there were 0 purple days in 2010, 2015, and 2020. The number of red days (unhealthy) has gone down as well. The number of yellow days (moderately unhealthy) has gone up, but this is because there are less red and purple days.

7. Return to the Investigation Tracker

Have students make notes in their investigation tracker based on big ideas they learned during this activity. Key takeaways:

  • Air quality is measured using a scale call the Air Quality Index (AQI)

  • The main air pollutants in the DC-Baltimore area are particulate matter (PM) and ozone.

  • Air quality in the DC-Baltimore area is improving

8. Formative Assessment

Show students this calendar and tell them that this is the July AQI data from the DC area for some time between 1995 and 2020. Based upon what they learned today, what year would they predict this data is from? How did they choose that year? How confident are they in their prediction?


AQI calendar.jpg


  • The actual month is July, 2006.

  • Students should be able to predict that this is likely in the 2005-2010 range (though they may also go as far as 2015) because it has 5 red/purple days (similar to 2005 & 2010) and 22 yellow/orange days (similar to 2015 & 2010)

  • They should also be fairly uncertain about the year, partly because they don’t know what year it is in the range, and partly because they know that conditions can vary from year to year.


Homework Suggestion: Have students show their parents or guardians how to find the AQI at home (using a computer or phone) and explain what it means.

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