Take a deep breath. In a single intake of air, your lungs swell with roughly 25 sextillion molecules, ranging from days-old compounds, to those formed billions of years in the past. In fact, many of the molecules you're breathing were likely exhaled by members of ancient civilizations and innumerable humans since. But what exactly are we all breathing? Amy Hrdina and Jesse Kroll investigate. [Directed by Sharon Colman, narrated by Alexandra Panzer, music by Miguel d'Oliveira]. 

Amy Hrdina and Jesse Kroll: What's in the air you breathe?

What's in the air you breathe?

Each breath contains 25 sextillion molecules, a mix from days past to billions of years, including ancient human exhales.

Air composition: 78% nitrogen from volcanic activity, 21% oxygen from microorganisms, and .93% argon from radioactive decay.

Modern air is a cocktail of natural and man-made compounds, including pollutants that can cause lung disease and DNA damage.