1) Layer 2) Layer 12 to 30 miles up 3) Ozone layer 
region in the upper atmosphere between about 10 and 50 km (6 and 30 miles) in altitude, in which there are appreciable concentrations of ozone and in ... [13 related articles]
Another name for the ozone layer.
stratospheric ozone layer, giving protection to the earth's surface due to intense absorption of harmful solar ultraviolet radiation by the gas.