UVBstraling

UVBstraling refers to ultraviolet B radiation, a portion of the ultraviolet spectrum with wavelengths roughly 280 to 315 nanometers. It is more energetic than UVA and is largely absorbed by the ozone layer, but some reaches the Earth's surface. In daylight, the amount of UVB varies with latitude, season, time of day, altitude, and cloud cover. Artificial sources include tanning beds and certain lamps used in laboratories.

Exposure to UVBstraling can cause skin damage and erythema (sunburn) within hours. It damages cellular DNA, notably forming cyclobutane pyrimidine dimers, which contributes to mutation and skin cancer risk with cumulative exposure. Repeated exposure also accelerates photoaging. Individuals with lighter skin typically experience greater acute effects at lower doses compared with darker skin types.

UVBstraling also drives the synthesis of vitamin D in the skin, converting 7-dehydrocholesterol to previtamin D3. This is a natural source of vitamin D for many people, but beneficial effects must be balanced against cancer and aging risks from UV exposure.

Measurement and protection: The UV Index provides a daily forecast of the potential for UV damage. Protective strategies include seeking shade, wearing clothing that covers the skin, wide-brimmed hats, sunglasses, and applying broad-spectrum sunscreen that blocks UVB. Indoor tanning beds emit UVB and UVA and are associated with increased skin cancer risk, leading health authorities to discourage their use. Ozone depletion can increase ground-level UVB.