NASA reports Arctic stratospheric ozone depletion hit record low in March

Ozone levels above the Arctic reached a record low for March, NASA researchers report. An analysis of satellite observations show that ozone levels reached their lowest point on March 12 at 205 Dobson units.While such low levels are rare, they are not unprecedented. Similar low ozone levels occurred in the upper atmosphere, or stratosphere, in 1997 and 2011. In comparison, the lowest March ozone value observed in the Arctic is usually around 240 Dobson units.