Ozone hole in early October 2015
Ozone hole in early October 2015
The ozone hole over Antarctica – imaged on 2 October 2015 – appears as a nearly circular area. The ozone concentrations are measured in Dobson units. If all the ozone molecules in the atmosphere were brought to ground level, for example, an ozone concentration of 200 Dobson units would correspond to a layer thickness of only two millimetres. This shows that ozone is, in fact, found only in trace amounts in the atmosphere – that is, it is a ‘trace gas’. Small amounts of this trace gas can have a large impact, in the same way that a little salt in soup can significantly affect the flavour.
