The glaziers who created gold-painted stained glass windows for medieval churches in Europe inadvertently developed a solar-powered nanotech air-purification system.

According to Zhu Huai Yong, an associate professor at Queensland University of Technology in Australia, the gold paint used in medieval-era stained glass windows purified the air when heated by sunlight.

"For centuries people appreciated only the beautiful works of art, and long life of the colors, but little did they realize that these works of art are also, in modern language, photocatalytic air purifier with nanostructured gold catalyst," said Zhu in a statement.

Zhu said that tiny gold particles found in medieval gold paint react with sunlight to destroy air-borne pollutants like volatile organic chemicals/compounds (VOCs), which are emitted from paints, lacquers, and glues, among other things.

"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," Zhu said.

When interacting with gold particles, sunlight creates an electromagnetic field that reacts with the oscillating electrons in the gold. This field resonates and breaks apart pollutants in the air, according to Zhu. The byproduct is small amounts of carbon dioxide, which is better than carbon monoxide in terms of human health.

Zhou expects his research will help make the production of chemicals at room temperature more cost effective and environmentally friendly.