Titanium dioxide has been researched for its ability to reduce air pollution. Ultraviolet light will release free electrons from material, thereby creating free radicals, which break up VOCs (Volatile organic compounds ) and NOx gases (nitric oxide and nitrogen dioxide). One form is superhydrophilic.

In 2014, Prof. Tony Ryan and Prof. Simon Armitage of University of Sheffield prepared a 10 meter by 20 meter-sized poster coated with microscopic, pollution-eating nanoparticles of titanium dioxide. Placed on a building, this giant poster can absorb the toxic emission from around 20 cars each day.

Italian company Italcementi designed a kind of cement, that is supposed to fight air pollution. It should break down pollutants that come in contact with the concrete, thanks to the use of titanium dioxide absorbing ultraviolet light. Some environmental experts nevertheless remain skeptical and wonder if the special material can 'eat' enough pollutants to make it financially viable. Jubilee Church in Rome is built from this kind of concrete.

The south side of the Jubilee Church features three large curved walls of pre-cast concrete. (The walls form segments of spheres.) Meier claims to have designed the church to minimize thermal peak loads inside. The large thermal mass of the concrete walls control internal heat gain; the result is less temperature variation, and supposedly more efficient use of energy. The walls also contain titanium dioxide to keep the appearance of the church white. Enrico Borgarello, the director of research and development for Italcementi, the company that designed the cement, claims that the cement destroys air pollution.

According to Borgarello: "When the titanium dioxide absorbs ultraviolet light, it becomes powerfully reactive, breaking down pollutants that come in contact with the concrete. It is particularly good at attacking the noxious gases that come out of a cars exhaust pipe."

Eco-Block, which was invented by the Hong Kong Polytechnic University in 2006, is an environmental friendly brick made from recycled materials and construction waste. On the surface layer, there is a special coating made from titanium oxide (TiO2). When activated by the sunlight, the titanium oxide can catalyze the decomposition of nitrous oxides into oxygen, water, sulphur, nitrates and other non-toxic solid compounds which can be washed away by water.

See also: Air Pollution

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