Did you know Denver typically ranks as one of the top 10 most polluted ozone cities in America?

We always hear our meteorologists talk about ozone levels in the Denver Metro area and how high they are, but most of us have no idea what all those numbers mean.

We asked 9NEWS' Cory Reppenhagen’s to make us smarter, and explain why Denver has it so bad. Watch in the video above.

If you want to check out the air quality color guide meanings for yourself, click here.