"Column ozone" refers to the layer of ozone gas present in a vertical column of the Earth's atmosphere above a specific location. It helps protect us from harmful ultraviolet (UV) radiation coming from the sun. Full definition
Total column ozone declined over most of the globe during the 1980s and early 1990s. (sciencedaily.com)
Figure 2: Total column ozone loss relative to pre-ozone hole conditions in the 1970s in percent (left) and total number of molecules (right)(1 DU = 2.69 molecules / cm2) averaged over 2010 - 2019, during September for the Southern Hemisphere and March for the Northern Hemisphere. (giss.nasa.gov)
The ozone datasets for total column ozone include total ozone and total ozone observations and the vertical ozone profile includes lidar, ozonesonde, Umkehr N - value and C - Umkehr. (woudc.org)