[[Sunlight]] has benefits that [[Vitamin D]] supplementation do not. # UV - **UVB** creates [[Vitamin D]] so its **better** but it burns (peaks midday) - **UVA** causes **aging** (steady through day so sunscreen early) **Generally, ordinary glass such as the glass windows in your home can filter out UVB rays but not UVA sun rays**. See... UV Index Does Not Predict Ocular Ultraviolet Exposure #ResearchToProcrastinate ![[UV-hourly-changes.png|400]] ## Ultraviolet A (UVA) UVA has a longer wavelength. It is associated with [[skin]] [[aging]]. UVA is constant through the day. [[Zinc oxide]] blocks more UVA than UVB ## UltraViolet B UVB has a shorter wavelength. It is associated with skin burning. UVB is what your skin uses to make [[Vitamin D]]. UVB mounts mid day. ## #Caution you still need suncreen early in the day if you want to avoid the aging.