DermUV
UVA
UVA is long-wavelength ultraviolet radiation (320–400 nm) that penetrates deeply into the dermis, drives photoaging, and contributes to melanoma.
UVA explained
UVA passes through window glass and clouds, and is present at near-constant intensity throughout daylight hours — unlike UVB, which peaks midday. PA+++ and 'broad-spectrum' labels indicate UVA protection. The critical wavelength must be ≥ 370 nm for FDA broad-spectrum status.
Related terms
Terms related to UVA connect the UV and sunscreen topic cluster.
Related DermUV pages
Continue with calculators and city UV forecasts.