The Earth can handle small amounts of pollution. But what happens when a lot of pollution enters the air? The air can't handle it and the pollution builds up. This means you breathe pollutants along with the oxygen you need.

Every day you breathe thousands of gallons of air. With that much air going into your lungs, even small amounts of air pollution present in each breath of air can harm your health.

High levels of ground-level ozone (smog) or fine particles (soot) can irritate your mouth, nose, and throat. This may make you cough more, make your throat feel scratchy and make your chest feel tight.

Do you know someone with asthma? Smog and soot can even make breathing problems like asthma worse. Smog and soot hurt kids and older adults – especially those with breathing problems. But did you "kno" that breathing in lots of soot can damage your heart, too? That's why it's important to know what our air quality will be like each day.

A network of monitors throughout central Indiana measures our air. Scientists use these numbers to come up with the Air Quality Index (AQI), which uses six different colors. These colors are green, yellow, orange, red, purple and maroon. The colors tell you how healthy the air is to breathe that day.

The first and best color is green, which means our air is good. The second color is yellow, which means our air is pretty good. The air in central Indiana is almost always green or yellow.

The third color is orange, which means our air is okay for most people. If the scientists on the Knozone team think we may have an orange day, they will call a Knozone Action Day. People that are sensitive to pollution (like those that have asthma or other breathing problems) should pay attention to their health.

The fourth color is red, which means the air is pretty bad for everyone. The fifth color is purple, which means the air is really bad for everyone. In central Indiana, we very rarely reach the red level.

The last color is maroon, which is really, really bad. Most of the time you won't see this color on the Air Quality Index. That's because people all across the county have worked really hard to make sure our air never gets this bad.