UVBlicht

UVB light, or ultraviolet B light, is a portion of the ultraviolet radiation spectrum with wavelengths from about 280 to 315 nanometers. It lies between UVA (315–400 nm) and UVC (100–280 nm). In natural sunlight, UVB contributes to the sun’s energy reaching the surface, though its amount varies with time of day, season, and atmospheric conditions. Artificial UVB sources include specialized lamps, UVB-emitting LEDs, and some tanning devices.

Biological effects of UVB are significant. The energy it deposits can cause direct DNA damage, contributing to sunburn and an increased risk of skin cancer with long-term or intensive exposure. At the same time, UVB stimulates the skin to produce vitamin D3, an essential nutrient. In medicine, narrowband UVB around 311–312 nm is used in phototherapy to treat conditions such as psoriasis, eczema, and vitiligo because it can be effective with a lower risk of erythema than broader UVB.

Sources and applications of UVB include the sun as the primary natural source and various artificial devices used in medical treatment, dermatology clinics, and research settings. UVB also plays a role in some horticultural experiments and materials testing, where controlled exposure is part of the study or product development.

Safety and regulation are important with UVB. Overexposure can damage eyes and skin, so protective eyewear, clothing, and shielding are recommended. In medical phototherapy, doses are carefully controlled and administered by professionals. Tanning devices are regulated in many regions, and usage guidelines typically discourage unsupervised exposure, especially for young people and individuals with fair skin.