Historical references

There are two primary forms of titanium dioxide commercially available: anatase and rutile. The rutile form is typically used in sunscreens due to its superior ability to handle UV rays and stability in the presence of UV light. The anatase form is typically used in other types of products, such as paint. Another plus of the rutile form is that its UVA protection extends past 400 nanometers, which is the upper limit of UVA.

Even though it is one of the most-produced chemicals, the real and potential benefits of titanium dioxide are not without controversies. Dust inhalation may cause breathing problems. Titanium dioxide has been classified by the International Agency for Research on Cancer as an Group 2B carcinogen, a “possible carcinogen to humans,” based on studies of rats that inhaled the substance.

Three aspects determine the performance of titanium dioxide as pigment and UV absorber.