Ultraviolet light rays (UVA and UVB)

Content provided by Healthwise

Ultraviolet light rays (UVA and UVB)

The sunlight that reaches the earth has ultraviolet A and ultraviolet B (UVA and UVB) rays. These ultraviolet rays are the main causes of damage to the skin from the sun. UVA and UVB rays affect the skin's sensitivity to sun exposure in different ways.

UVA:

Can pass through window glass.
Is not affected by a change in altitude or weather.
Is present all day and every day of the year.
Penetrates deep into skin layers.
Is 20 times more abundant than UVB rays.
Causes long-term skin damage.

UVB:

Cannot pass through window glass.
Causes sunburn.
Causes tanning.
Helps the body make vitamin D.
Is more intense:
- During the middle of the day.
- In the summer.
- At high altitudes and near the equator.
Can cause skin cancer and cataracts.

Use a sunscreen that has a sun protection factor (SPF) of at least 30 or higher. Sunscreens that say "broad-spectrum" can protect the skin from ultraviolet A and B (UVA and UVB) rays. Sunscreens come in lotions, gels, creams, and ointments.

Credits

Print Email SHARE

Author	Jan Nissl, RN, BS
Editor	Susan Van Houten, RN, BSN, MBA
Associate Editor	Michele Cronen
Associate Editor	Tracy Landauer
Primary Medical Reviewer	William M. Green, MD - Emergency Medicine
Specialist Medical Reviewer	Alexander H. Murray, MD, FRCPC - Dermatology
Last Updated	December 28, 2007

Print Email Twitter Facebook MySpace AIM More

Last updated:	December 28, 2007
Author:	Jan Nissl, RN, BS
Reviewed By:	William M. Green, MD - Emergency Medicine, Alexander H. Murray, MD, FRCPC - Dermatology
Editors:	Susan Van Houten, RN, BSN, MBA, Tracy Landauer

This information is not intended to replace the advice of a doctor. By using AOL Body, you indicate that you have read, understood, and agreed to our Terms of Service, and AOL Body Advertising Policy. Read more about our content partners.