"The conventional method to evaluate the activity of photoactive fabrics is discoloration of spots under radiation. Organic dyes... coffee... wine... juice... make-up, and sweat... were used... Complete discoloration of spots can be achieved on the surface of photoactive fabrics after long-term irradiation."
Titanium dioxide, also known as titanium(IV) oxide or titania, is the inorganic compound derived from titanium with the chemical formula TiO2. When used as a pigment, it is called titanium white, Pigment White 6 (PW6), or CI 77891. It is a white solid that is insoluble in water, although mineral forms can appear black. As a pigment, it has a wide range of applications, including paint, sunscreen,
"In two studies of rats that inhaled titanium dioxide, one observed an excess incidence of lung tumours... No increases were observed among mice and hamsters exposed intratracheally. Other studies that used different routes of administration did not observe excesses in tumour incidence."
"Titanium dioxide was first produced commercially in 1923, primarily for pigment production. Relatively small quantities are used for non-pigmentary purposes."
"TiO2 has been classified in humans and animals as biologically inert... and is widely considered to be a "natural" material..."
"The annual worldwide production of titania powder in 2005 has been estimated to be around 5 million tons... The proportion of nano-sized titania is estimated to have been approximately... 10% by 2015... with an exponential increase over the past decade."
"[I]ts light-scattering properties and very high , which mean that relatively low levels of the pigment are required to achieve a white, opaque coating."
"Most titanium dioxide pigment is produced from mineral concentrates by the chloride or sulfate process, either as the rutile or as the anatase form."