Ozone (total column)

The total amount of ozone gas stacked in a column of atmosphere from the ground to space. Most of it sits high up in the stratosphere, where it shields life from harmful ultraviolet rays.

Why it matters

The ozone layer blocks dangerous UV radiation, so tracking total column ozone is how scientists watch the Antarctic ozone hole heal and monitor harmful ozone pollution near the ground.

Where you’ll meet it

• OMI on Aura has tracked global ozone and the ozone hole for nearly two decades.
• TROPOMI on Sentinel-5P continues high-resolution ozone monitoring.
• TEMPO measures ozone and other pollutants hourly over North America during daylight.

In plain terms

It’s like measuring how thick your sunscreen layer is — the ozone column is the planet’s UV shield, and scientists keep checking it isn’t wearing thin.