The thickness of ozone layer is measured in terms of
Dobson Units (DU) are used to measure how thick the ozone layer is.
One Dobson Unit (DU) is equal to a layer of ozone that is 0.01 mm thick if it were squished together into a single layer at room temperature and pressure. There is an average of about 300 DU in most parts of the world, but it can be anywhere from 200 to 500 DU.
The Dobson Units are named for G.M.B. Dobson, a scientist who made the first device to measure the amount of ozone in the air.