Se denomina capa de ozono, a la zona de la estratosfera terrestre que contiene una concentración relativamente alta de ozono.Esta capa, que se extiende aproximadamente de los 15 km a los 50 km de altitud, reúne el 90 % del ozono presente en la atmósfera y absorbe del 97 % al 99 % de la radiación ultravioleta de alta frecuencia. La capa de ozono fue descubierta en 1913 por los físicos franceses Charles Fabry y Henri Buisson. Sus propiedades fueron examinadas en detalle por el meteorólogo británico G.M.B. Dobson, quien desarrolló un sencillo espectrofotómetro que podía ser usado para medir el ozono estratosférico desde la superficie terrestre. Entre 1928 y 1958 Dobson estableció una red mundial de estaciones de monitoreo de ozono, las cuales continúan operando en la actualidad. La unidad Dobson, una unidad de medición de la cantidad de ozono, fue nombrada en su honor.

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The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. The ozone layer contains less than 10 parts per million of ozone, while the average ozone concentration in Earth's atmosphere as a whole is about 0.3 parts per million. The ozone layer is mainly found in the lower portion of the stratosphere, from approximately 20 to 30 kilometres (12 to 19 mi) above Earth, although the thickness varies seasonally and geographically. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson. Measurements of the sun showed that the radiation sent out from its surface and reaching the ground on Earth is usually consistent with the spectrum of a black body with a temperature in the range of 5,500–6,000 K (5,227 to 5,727 °C), except that there was no radiation below a wavelength of about 310 nm at the ultraviolet end of the spectrum. It was deduced that the missing radiation was being absorbed by something in the atmosphere. Eventually the spectrum of the missing radiation was matched to only one known chemical, ozone. 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 amount of ozone overhead, is named in his honor. The ozone layer absorbs 97 to 99 percent of the Sun's medium-frequency ultraviolet light (from about 200 nm to 315 nm wavelength), which otherwise would potentially damage exposed life forms near the surface. The United Nations General Assembly has designated September 16 as the International Day for the Preservation of the Ozone Layer. Venus also has a thin ozone layer at an altitude of 100 kilometers from the planet's surface.

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