Stained glass windows that are painted with gold purify the air when they are lit up by sunlight, a team of Queensland University of Technology experts have discovered. Associate Professor Zhu Huai Yong, from QUT's School of Physical and Chemical Sciences, said that glaziers in medieval forges were the first nanotechnologists who produced colours with gold nanoparticles of different sizes.Professor Zhu said numerous church windows across Europe were decorated with glass coloured in gold nanoparticles."For centuries people appreciated only the beautiful works of art, and long life of the colours, but little did they realize that these works of art are also, in modern language, a photocatalytic air purifier with nanostructured gold catalyst," Professor Zhu said.He said tiny particles of gold, energized by the sun, were able to destroy airborne pollutants like VOCs, which may often come from new furniture, carpets and paint in good condition."These VOCs create that ‘new' smell as they are slowly released from walls and furniture, but they, along with methanol and carbon monoxide, are not good for your health, even in small amounts," he said.