This is one of the most common questions asked of Team Wolff:
What is the Difference Between UVA, UVB and UVC?
Ultraviolet (UV) light is energy from the sun that cannot be seen, but its effects can be observed upon all living things. UV energy is organized into three distinct ranges: UVA, UVB and UVC. This spectrum of energy is measured in nanometers (nm), with one nanometer equaling one billionth of a meter. The relationship between the length of the wave and the amount of energy: the longer the wavelength, the lower the energy.
Ultraviolet light types are organized from the shorter (and higher energy) wavelength (UVC) to the longer (and lower energy) wavelength (UVA), and each type has its own location on the electromagnetic spectrum. The UVC energy range is 200-280nm, UVB is 280-320nm, UVA2 is from 320-340, and UVA1 from 340-400nm. Visible light is in the range of 400-780nm.
Typically, the longer the wave, the less harmful the energy is to humans exposed to it; the shorter the wave, the more intense. Each has a beneficial purpose. For instance, while UVC is the most powerful of ultraviolet rays and considered harmful to humans, hospitals use germicidal lamps that emit UVC (253.7nm) to sterilize surgical instruments, water, and the air in operating rooms because it can destroy bacteria and viruses.
When we spend time in the sun, we are primarily exposed to UVA and UVB light. UVC rays are generally filtered out by the earth’s ozone layer. Some scientists hypothesize that erosion of the ozone layer may allow some UVC rays to reach the earth, but most research has been inconclusive.
UVA waves are longer than other ultraviolet waves and can penetrate human skin to the deeper layers, known as the dermis. While it is possible to darken only existing pigment in the skin with UVA alone, this can only be accomplished with exposure to high levels of UVA, which may have long-term adverse effects.
UVB light waves are shorter than UVA waves, principally affecting the upper layers of the skin – the epidermis. UVB waves stimulate the upper layers of the skin to produce melanin, the pigment that forms a coating around other skin cells to protect them from overexposure to the sun. This process is known as pigmentation. Although UVB cannot penetrate the skin as deeply as UVA can, overexposure to UVB is more likely to cause sunburn.
A good tanning lamp needs a balance of UVA and UVB. UVB stimulates melanin production and can burn the skin if overexposed; UVA2 acts a lot like UVB, with melanin production and some pigment darkening; it is also closely associated with elastosis (photoaging, wrinkles). UVA1 penetrates deeper past the surface of the skin and is primarily responsible for pigment darkening (tan). Newer lamp technology focuses on providing enough UVB to stimulate the melanin and aid in production of vitamin D, plenty of UVA1, and less of UVA2. This combination results in robust pigmentation, very effective tanning and a natural protection against damage from the sun.
Newer lamp technology focuses on providing enough UVB to stimulate the melanin and aid in production of vitamin D, plenty of UVA1, and less of UVA2.
