The ozone layer, the natural UV-filter of the earth, is getting thinner. As a result, more harmful rays from the sun are passing through this natural barrier. UVA and UVB rays passing through the barrier can cause DNA damage in the skin which can lead to photo aging and more critically skin cancer.
There are two physical filters used in sunscreen products approved by Food and Drug Administration (FDA) and European Union (EU); Zinc Oxide (ZnO) and Titanium dioxide (TiO2). Between these two systems, ZnO is the only sunscreen ingredient that extensively covers both UVA and UVB as reported by FDA.