Traditionally, UV-filters are categorized as either chemical or physical. The big difference is supposed to be that chemical agents absorb UV-light while physical agents reflect it like a bunch of mini umbrellas on top of the skin. While this categorization is easy and logical it turns out it's not true. A recent, 2016 study shows that inorganic sunscreens work mostly by absorption, just like chemical filters, and only a little bit by reflection (they do reflect the light in the visible spectrum, but mostly absorb in the UV spectrum).

3. Photocatalysis The photocatalytic properties of anatase make it valuable for environmental applications such as air and water purification. Manufacturers are exploring its potential in self-cleaning surfaces and photocatalytic reactors, which can degrade pollutants under UV light.