The ozone layer protects the Earth from the sun's
ultraviolet rays. But the ozone layer is getting thinner, and more ultraviolet
radiation is reaching the Earth. Health officials urge people to protect
themselves from the sun's damaging rays. They recommend that people spend less
time in the sun; wear protective clothing, including wide-brimmed hats, when in
the sun; wear sunglasses that block ultraviolet rays; and apply sunscreen. (Grolier New Book of Knowledge Encyclopedia)