1. Activate students' prior knowledge about air quality.

Show the Highland Park Optimist Club banquet in 1954 image. (Click on the link in the media carousel above and download using the arrow in the lower right corner of the window.) Tell students that bad air quality has a negative effect on human health. Air quality was poor in the United States before Clean Air Act regulations went into effect in 1970. Many areas around the world still experience very poor air quality. Ask:

• Why do you think air quality is better in the United States today than it was before 1970? (Air quality is better because the Clean Air Act set air quality standards that states and localities had to meet. They reduced their emissions to meet the standards, and the air quality improved.)

• What causes poor air quality events? (There are many causes of poor air quality events. Human actions [burning fuels and using volatile organic compounds] put pollutants into the air. Natural events [forest fires and volcanic eruptions] can also affect air quality.)

• Are human processes the only causes of air pollution? (Humans are not the only causes of air pollution. Forest fires and volcanic eruptions are two natural causes of poor air quality.)

Tell students that air quality is measured by the air quality index. Show students the Air Quality Index, and then access the Air Now: Today’s AQI Forecast website and show the air quality forecast map for the United States. Ask:

• Where is the air quality forecast to be the worst in the United States today? (Answers will vary depending on the day.)

• What do you think is the cause for the poor air quality in the United States today? (Depending on the area of the country, the poor air quality could be due to fires, emissions from power plants and factories, and/or emissions from vehicles. Stagnant weather patterns can contribute to poor air quality events.)

• How do you think scientists forecast air quality? (Scientists use data from real-time monitoring stations to measure the level of pollutants in particular areas and weather forecasts to predict where wind will blow pollutants (or leave pollutants over a particular location).)

2. Discuss the role of uncertainty in the scientific process.

Tell students that science is a process of learning how the world works and that scientists do not know the “right” answers when they start to investigate a question. Let students know that they can see examples of scientists' uncertainty in forecasting air quality. Show the Forecast of Air Quality on December 10, 2013 image and Air Quality on December 10, 2013 image. (Click on the link in the media carousel above and download using the arrow in the lower right corner of the window.) Tell students that these are snapshots of the air quality forecast and the real-time air quality in the United States on December 10, 2013. Ask:

• Did the forecast accurately predict which areas would have poor quality air? (The forecast air quality overlaps with many of the poor air quality areas, but it does not cover all of them. The air quality in some areas (Northern California) is much worse than the forecast predicted.)

• Why do you think scientists did not accurately predict the air quality for more of the United States? (Student answers will vary. The air quality forecast is affected by human activities that may not be easily predicted.)

Tell students they will be asked questions about the certainty of their predictions. Let students know they should think about what scientific data is available as they assess their certainty with their answers, and encourage them to discuss the scientific evidence with each other to better assess their level of certainty with their predictions.

3. Have students launch the Measuring Air Quality interactive.

Provide students with the link to the Measuring Air Quality interactive. Divide students into groups of two or three, with two being the ideal grouping to allow groups to share a computer workstation. Tell students that they will be working through a series of pages of data with questions related to the data. Ask students to work through the activity in their groups, discussing and responding to questions as they go.

NOTE: You can access the Answer Key for students' questions—and save students' data for online grading—through a free registration on the High-Adventure Science portal page.

Tell students that this is Activity 2 of the Will the Air Be Clean Enough to Breathe? lesson.

4. Discuss the issues.

After students have completed the activity, bring the groups back together and lead a discussion focusing on these questions:

• What groups of people are most at risk from poor air quality? People who work outdoors are most at risk, followed by those with breathing problems, such as asthma, emphysema, and COPD (chronic obstructive pulmonary disease).

• What do officials suggest people do when bad air quality is forecast?  (When bad air quality is forecast, officials suggest limiting outdoor activities.)

• What might happen to air quality if the population continues to grow? (If the population continues to grow, air quality might decrease, especially in areas of the world where air quality is already bad a lot of the time.)

• How might humans mitigate bad air quality events in the future? (Humans might be able to mitigate bad air quality events through technology. Technology could be developed that removes more emissions from cars, factories, and power plants. Technology could also change so that manufacturing and transportation methods don't require burning of fuels that release pollutants into the air.)