What unit is used to measure ozone concentration?

Ozone concentration is often measured in Dobson Units, which provide a specific measurement of the amount of ozone in a column of the atmosphere. One Dobson Unit corresponds to a layer of ozone that would create a pressure of 0.01 millibars at a temperature of 0 degrees Celsius. This unit is particularly useful when discussing the ozone layer in the stratosphere, as it helps quantify the total amount of ozone present in a vertical column of air from the surface to the top of the atmosphere.

Other units like parts per million may apply to gases in general, but for stratospheric ozone, the Dobson Unit is the standard. Atmospheric pressure is a measure of the weight of the air above a certain point and doesn't directly quantify ozone concentration, while degrees Celsius measures temperature rather than gas concentration. Hence, the use of Dobson Units is crucial for understanding and discussing ozone levels specifically in the context of atmospheric studies.