Two NYU grad students have created high-tech sweatshirts that change colour when exposed to pollution.

Nien Lam and Sue Ngo created the sweatshirt, which is emblazoned with pink lungs that suddenly show blue veins when exposed to dirty air, during a class on wearable technologies in the interactive telecommunications program at Tisch School of the Arts.

"The organs in your body are invisible to you, just like pollution and the other silent killers out there," the New York Daily News quoted Lam, 32, who lives on the upper West Side, as saying.

Ngo, 27, of Fort Greene, Brooklyn added: "We wanted to bring up that visualization, bring the inside out. This is a stark reminder for yourself and others around you."

A dime-sized carbon monoxide sensor attached to the sweatshirt detects pollution from cars, factories, and even second-hand smoke.

It sits on a micro-controller programmed to send electrical currents through the shirt, warming wires that run under the lungs - or on some shirts, a heart.

Because the organs are made of thermochromic fabric that changes colour dramatically when heated, blue veins become visible when the sensor finds toxins in the air.

The duo hope to find a way to cheaply mass produce the shirts, which use about 60 dollars worth of material, and they are also experimenting with other kinds of sensors, including a booze detector.

"If you were drinking alcohol, the sensor would pick up the fumes and change the colour of the liver," Ngo stated.