Frequently Asked Questions

• What is the ozone layer?

  That level of the atmosphere which encompasses a peak in ozone concentrations. As electromagnetic radiation comes in from the sun and hits the earth's atmosphere, certain wavelengths in the ultraviolet range (180-240 nanometers) are absorbed by and break apart oxygen molecules (which are made of two oxygen atoms). Some of the resulting unattached pairs of oxygen atoms then recombine into triplets to form ozone. The higher up in the atmosphere you go, the thinner the air is, and thus the less oxygen there is to absorb the 180-240 nm ultraviolet to form ozone; this means that ozone amounts tend to decrease you go higher. The highest ozone concentrations are found at 12 to 30 km, in what is called the 'ozone layer'.