Smog City is an interactive air pollution simulator that shows how your choices, environmental factors, and land use contribute to air pollution. In Smog City you're in control so your visit can be a healthy or unhealthy experience depending on the decisions you make. You'll see how ground-level ozone, the biggest part of summertime smog, increases or decreases when you spend a day in Smog City. And since ozone can irritate respiratory systems, cause breathing difficulty, coughing, and chest pain, knowing how and why ozone forms and what you can do about it is important to the residents of Smog City and everyone else on the planet.