How does UVA radiation affect the skin?

UVA radiation is known for its ability to penetrate deeply into the skin, affecting the dermis where collagen and elastin fibers are located. This deep penetration contributes to long-term skin damage, including premature aging, which manifests as wrinkles, loss of skin elasticity, and overall skin texture changes. Unlike UVB radiation, which primarily affects the surface layer and is responsible for sunburn (erythema), UVA can have more insidious effects since it can damage skin cells over time without producing immediate symptoms.

The other options describe effects that are associated with either background exposure or different types of radiation. For instance, providing an immediate tan is typically associated with a combination of both UVA and UVB, but it doesn’t reflect the long-term impact. Skin erythema is more related to the effects of UVB radiation and not primarily UVA. Finally, vitamin D production is primarily stimulated by UVB radiation, not UVA, meaning it doesn't contribute to this process. Therefore, the characterization of UVA radiation's effect on the skin as primarily leading to aging is accurate and highlights its significant impact on skin health.