High Quality Content by WIKIPEDIA articles! The ozone layer is a layer in Earth`s atmosphere which contains relatively high concentrations of ozone (O3). This layer absorbs 97–99% of the Sun`s high frequency ultraviolet light, which is potentially damaging to the life forms on Earth. It is mainly located in the lower portion of the stratosphere from approximately 20 to 30 kilometres (12 to 19 mi) above Earth, though the thickness varies seasonally and geographically. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations, which continue to operate to this day. The "Dobson unit", a convenient measure of the columnar density of ozone overhead, is named in his honor.