Chemical (organic) UV filters are the most popular kind of sun protection due to their aesthetically pleasing application to the skin. However, their use raises some serious health concerns. Chemical UV filters have also been implicated in ecological damage, due to their effect on the marine environment.
Mineral (inorganic) filters sit on top of your skin creating a protective barrier that does not penetrate your skin. Zinc oxide naturally protects against both UVA & UVB rays, meaning it has broad spectrum protection. Titanium dioxide effectively blocks UVB rays however it does not fully protect against UVA.
Broad spectrum Protection
UVB is the primary cause of sunburn by causing inflammation of the skin cells.
UVA is the cause of long term skin damage including loss of elasticity and wrinkling, penetrating much deeper into the skin than UVB.
Both UVA and UVB play a role in skin damage and the formation of skin cancer. When a UV filter blocks both UVB and UVA it is considered to be full spectrum protection.