Sunscreen with high SPF needed at high altitudes: 8-10% increase in sun exposure for every thousand feet of elevation

Golfers playing in Vail, Colorado, at 2500 meters (roughly 8200 feet) above sea level, got significantly more burn protection from sunscreen with a sun protection factor (SPF) of 70+ compared to one with an SPF of 15.

There is 8-10 percent increase in sun exposure for every thousand feet of elevation. In the summertime, you can get anywhere from 40 percent to 50 percent greater sun intensity than at sea level.

References:
Sunscreen with high SPF needed at high altitudes, Reuters.

What sunscreen to use for children?

Study confirms sunscreen prevents melanoma http://goo.gl/16Vqd

Can You Get Sunburned Through a Car Window? http://goo.gl/M7Fwv - No, but penetrating UVA rays may be related to left-sided skin cancers.

Related:

Melanoma - JAMA Patient Page illustrates the ABCDE of diagnosis, 2011.

Image source: Amazon, for illustration only, not a suggestion to buy any products.
Only 25% of Children Wear Sunscreen Regularly. WebMD, 2012.