What Is A Sunburn?

A sunburn is caused by exposing your skin to too much ultraviolet (UV) light from the sun, that is, lightwaves that measure approximately 200-400nm. UV light can be broken down into 4 component parts that include:

• Ultraviolet A1 (UVA1), 340-400nm
• Ultraviolet A2 (UVA2), 320-340nm
• Ultraviolet B (UVB), 290-320nm
• Ultraviolet C (UVC), 200-290nm

There are two major types of UV sun damage: UVA-type damage, with light wavelengths of 340-400nm, and UVC-type damage, which includes light wavelengths of up to 340nm. UVA-type damage can cause the skin to tan and may cause very weak burns, while UVC-type damage causes skin to burn.

Adapted from an article by David I. McLean, MD, and Richard Gallagher, MA.

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