At the Amundsen-Scott South Pole Station, meteorologist Timothy Markle prepares to launch a weather balloon. The balloons must first be heated to regain their elasticity, which is robbed from them in storage by the -4 degrees Fahrenheit surface temperatures in the southern hemisphere's summer.

This weather balloon will mostly measure temperature, air pressure, and wind speed, but others sample the air for the concentration of various gases like carbon dioxide and oxygen. The air sampled from the South Pole's clean air sector (a zone where air traffic, land vehicles, and even foot traffic is strictly limited) is touted as the cleanest air on Earth.