Types of Ultraviolet Light: UVA, UVB, and UVC

Ultraviolet light, a form of energy that is part of the electromagnetic radiation spectrum, exhibits shorter wavelengths than visible light but longer wavelengths than X-rays. This form of energy is usually measured in nanometers (nm) – a unit equal to one billionth of a meter or one thousandth of a micron. Ultraviolet light, spanning between 200-400 nm, consists of three categories: UV-A, UV-B, and UV-C. Natural sources like sunlight radiate UV light, though it’s also produced artificially in numerous systems.

Below is a summary of each category with their distinct attributes and potential advantages and disadvantages:

UV-A

• Wavelength: 400-320 nm
• Considered as the least harmful among UV types
• Contributes to 90-95% of the total UV radiation on Earth
• Commonly utilized for polymerizing UV adhesives and in fluorescent inspection processes

UV-B

• Wavelength: 320-280 nm
• Known to cause sunburn and skin cancer
• Accounts for 5-10% of UV radiation on Earth
• Frequently used to solidify UV inks and lacquers as UVB helps reduce surface tack

UV-C

• Wavelength: 280-200 nm
• The most damaging type of UV; however, it does not reach the Earth due to atmospheric filtration
• Present in artificial sources such as welding torches and certain mercury bulbs
• Often used for sterilization and germicidal applications