Lab Notes: What we can learn from the world’s cleanest air

We often hear about places where the air quality is bad, even dangerous, but what about where the air is the cleanest on Earth? That air can be found blowing onto the north-west tip of Tasmania at Kennaook/Cape Grim, where an air pollution station has quietly been keeping track of how humans have changed the makeup of our atmosphere for 50 years. So what does the world's cleanest air tell us?