SUN:  We can’t live with it; we can’t live without it
By Brian P. Maloney, MD, FACS

Like so many of us, I grew up in the sun generation.

The savage tan was in.  If you had a tan you were considered healthy, and if you didn’t you probably had some life threatening illness.

Models in almost all the magazines had deep tans as they promoted their products. Ahhhh, the seventies and eighties were great times…..

Until now, when skin cancers are the fastest increasing type of cancer!   The harmful effects of all those years of sun worshiping are rearing their ugly heads.
Unsightly liver spots, scaly areas on our skin, changes in our moles and wrinkles are the reminders of the hours of baby oil and accelerators under the sun.

Maintaining a ‘killer tan’ was very similar to cigarette smoking early on, which was considered a cool and healthy thing to do.  Only later the harmful and fatal side of smoking became apparent.

Yet unlike cigarette smoking the sun does provide an important and necessary role for our bodies. It is required for the body’s management of calcium. In the next couple columns I will share some of the new developments of sun exposure- the facts. This will be followed by the consequences of sun exposure, and update on skin cancers and rejuvenation of sun-damaged skin.

Sun Facts

The sun’s rays can be divided into ultraviolet A(uvA), B(uvB), and C(uvC). UvA was thought to be the healthy ray, being associated with tanning. This is the ray that most tanning beds use. It is pretty constant from sun up to sun down. UvB rays are most intense between the hours of 10 am and 2 pm. This and UvC were considered the bad rays.

Fifteen to fifty km above the surface of the earth resides one of the main filters of ultraviolet radiation-the ozone layer. Ozone at this level is very beneficial; however on the earth’s surface, combined with pollution it can cause difficulty breathing.

Scientists in the seventies suspected chlorofluorocarbons of destroying the ozone. They felt it would take a hundred years to have any effect. However in 1985 British scientists discovered low ozone levels over Haley Bay, Antarctica.

In March of 1993 thinning over the North Pole was discovered. Another disheartening discovery occurred in 1993 when ozone depletion was found over heavily populated mid-latitudes of the northern hemisphere. The impact this has had on all of us is significant. The numbers of skin cancers are increasing dramatically. Cataracts are also up. To reduce our ultraviolet radiation exposure I would like to review some facts.

The sunlight that reaches us contains about .5%UvB radiation. This is responsible for most of the effects of sunlight on our bodies. For every kilometer increase in altitude the ultraviolet flux increases by about 6%.

Seasonal ultraviolet exposure has little fluctuation in the tropics, and significant seasonal variation in more temperate areas. There is more UVB radiation in summer months in the United States.

Bacteria and viruses are inactivated by ultraviolet radiation (UVR).

Clouds. Water in clouds decrease the infrared rays more than the ultraviolet rays, making it easier to burn without feeling hot. There is generally no change in UVR with light clouds. Complete coverage with light clouds may decrease UVR to 50% compared with a clear day. Heavy clouds can completely eliminate UVR even in summertime.

Reflection The reflected light off of the ocean may be as low as 7%. Gypsum sand reflects 25% of UVB and snow 30-80%.
UVB penetrates to an incredible depth of .1mm. Yes, a tenth of a millimeter. Stay tuned to next month’s article to discover how this culprit can have consequences throughout the body after a reaction in the superficial layers of the skin.