Another name for smog is ground-level ozone. Smog is the brown haze you see above the city's skyline, mostly in the summer months. Like the air, smog is made up of a lot of different things. But mostly it's made up of ground-level ozone. Smog is bad for our environment and our health.

But I thought ozone was good?
Ozone is good up high, but bad nearby. The ozone layer is way up in the Earth's atmosphere. It protects us from the sun's harmful rays. On the ground, ozone is bad.

How is smog made?
Did you "kno" that there's a recipe for smog? It is heat plus chemicals equals smog.

The chemicals come from a variety of sources. Most come from automobile, small engine (like your lawnmower), and industrial source emissions. Because smog is man-made, there are lots of ways we can fight its formation.

Is there a smog season?
Yes. Scientists in central Indiana monitor for smog from April 1 through September 30. Why? Well, I'm sure you know that it gets really hot outside in the summer. Heat from the sun helps to create smog.