Dobson spectrophotometers  can be used to measure both total column ozone and profiles of ozone in the atmosphere. Ozone is tri-atomic oxygen, O3; ozone molecules absorb harmful UV light in the atmosphere before it reaches the surface of the earth.
Using Dobson spectrophotometers, one can determine both the overall ozone content and ozone layers within the atmosphere. Ozone, made up of three oxygen atoms (O3), absorbs harmful UV radiation from the atmosphere, protecting the Earth’s surface.