The World Health Organization, the U.N. Environment Program, and other agencies are launching a campaign to get children to stay out of the sun. The WHO says children are particularly vulnerable to getting skin cancer and cataracts later in life from early over-exposure to ultra-violet radiation. The World Health Organization says a certain amount of ultra-violet radiation is necessary to maintain a healthy body. But, too much can kill.

WHO says every year, there are between two and three million new cases of non-malignant melanomas and more than 130,000 new cases of melanoma cancers worldwide. An estimated 66,000 people die from melanoma and other skin cancers.

Coordinator of WHO's Radiation and Environmental Health Unit, Mike Repacholi, says children, who are most vulnerable and most exposed, are disproportionately affected by ultra violet, UV, radiation.

"We know that the child's skin is obviously more sensitive," said Mr. Repacholi. "Even a short time in the sun can produce serious sunburn. Single sunburns during childhood can significantly increase the risk of developing skin cancer in later life. Obviously, the majority of a person's lifetime UV exposure is received before age 18."

WHO says children and adults alike are at risk from skin cancer and cataracts because of the thinning of the ozone layer. Recent scientific findings show that the ozone layer is recovering, but the process of restoration will last another 40 years. Until then, scientists warn people to protect themselves from the sun's harmful rays.

Dr. Repacholi says people often are unaware of the health risks because the effects of exposure often do not appear until many years later. Furthermore, he says people think a tan is sign of good health.

"And, it looks nice," added Dr. Repacholi. "But, tanning is really just the body's mechanism of trying to defend itself against more UV exposure. And, this is important to know that the body is producing melanin within the skin to absorb the UV before it gets to the lower structure of the skin and does real damage."

The U.N. Health and Environmental agencies are issuing new educational materials to be used in schools on how to minimize the harmful effect of UV radiation. The WHO notes thousands of schools in the United States and Australia have been running successful sun-protection programs for years.

Health experts advise children to avoid the sun between 10:00 a.m. and 3:00 p.m. And, they say those children who go out to play in the sun should wear a hat, a long sleeved shirt, sunglasses and apply sun screen to parts of the body that are exposed.