As you push Smog City's control buttons and twist its dials, you'll learn a lot about the relationship between weather conditions and different types of smog-forming pollutants. For example, as you increase the strength of the inversion layer by moving it lower to the ground, you'll discover that pollution trapped beneath it will build up to unhealthy levels. Increase wind speed and air pollution clears out, leaving the residents of Smog City breathing easy.

You'll also learn how transportation choices make a real difference in air pollution levels. You'll see your choices reflected in the animated cityscape. Hit the Start button and watch as the selections you've made affect the air quality throughout a day in Smog City. As the sun sets on Smog City, you'll see the health result on the Air Quality Index graph.

  Press the Reset button, then increase population to the maximum. Press Start. What emissions settings do you change to move ozone levels into the healthy range?  

  Press the Reset button, then increase the population and turn the emissions knobs to the maximum settings. Change the weather conditions. Press Start. What happens to ozone levels?

  Press the Reset button, then change the weather controls (set maximum temperature to 120F, create a low inversion level, calm winds, and sunny skies), then increase population to the maximum. Press Start. Can you find ways to reduce ozone levels?  

  Press the Reset button, then set the temperature to 110F and winds to calm. Vary the emissions knobs, press Start, and discover which source contributes the most to ozone air pollution.