Windows block varying amounts of light, particularly different types of ultraviolet (UV) radiation. While they significantly reduce UV-B rays, they allow a considerable amount of UV-A rays to pass through.
Here's a more detailed breakdown:
- UV-B Rays: Home windows block the majority of UV-B rays. These are the rays primarily responsible for sunburns.
- UV-A Rays: Windows block only about 25% of UV-A rays. These rays penetrate deeper into the skin and contribute to premature aging.
Therefore, while you are unlikely to get a sunburn while indoors near a window, prolonged exposure to sunlight streaming through windows can still contribute to skin damage over time due to the UV-A rays that penetrate.
