Medieval stained-glass windows colored in gold nanoparticles help purify air when lit by the sun, a new study finds.

"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 Huai Yong, a material scientist at the Queensland University of Technology.

When energized by the sun, tiny gold particles can destroy certain airborne pollutants. These pollutants, called volatile organic compounds, create the "new" smell often detected in new furniture, carpets and paint in good condition. Even in small amounts, these compounds, like methanol and carbon monoxide, are not good for your health.