Ultra Violet rays
There are 2 basic types of ultra violet (UV) rays in the sunlight that are hitting the earth; UVA and UVB rays. Both play a role in the formation of skin cancer. Approx. 95% of the sun light hitting the earth are UVA rays. UVA rays are not filtered by clouds nor absorbed by the ozone layer like UVB rays. UVA rays can penetrate windows and clouds! Even though UVB rays make out only 5 %, they are much more intense than UVA rays.