The UN weather agency says the depletion of the ozone layer shielding Earth from damaging ultraviolet rays has reached an unprecedented low over the Arctic this spring, because of harmful chemicals and a cold winter.
The World Meteorological Organization said Tuesday that the Earth's fragile ozone layer in the Arctic region has suffered a loss of about 40 percent from the start of winter until late March exceeding the previous seasonal loss of about 30 percent.
The Geneva-based agency blamed the loss on a build-up of ozone-eating chemicals once widely used as coolants and fire retardants in a variety of appliances and on a very cold winter in the stratosphere, the second major layer of the Earth's atmosphere.
Arctic ozone conditions vary more than the seasonal ozone "hole" that forms high in the stratosphere near the South Pole each winter and spring.
AP