Sunscreen protects skin from the sun’s harmful ultraviolet rays, which come in two forms – UVA and UVB rays.
UVA rays are most commonly associated with skin aging; these beams that give us daylight, cause fine lines, wrinkles, and age spots that make skin look prematurely older. UVA rays have the ability to pass through glass, meaning skin is exposed while you are driving and standing or sitting in front of windows with the blinds open.
UVB rays are the rays most commonly associated with sunburns. Unlike UVA rays, UVBrays cannot pass through glass. Both UVA and UVB rays are carcinogens (cancer-causing), which is why sunblocks should be integral part of skin care routine as it offers broad-spectrum protection against both types.
Sun protections vary in which rays they protect you from. SPF is used to rate a sunscreen's ability to protect against just UVB rays, where UPF measures both UVA and UVB protection. - 4 minutes ago