Air pollution is oftentimes invisible, but it can cause a lot of harm. The American Lung Association reports that six in 10 Americans live in places with dangerous levels of air pollution, such as carbon monoxide. This chemical, which comes primarily from cigarette smoke and vehicles, inhibits your body’s ability to transfer oxygen to organs and tissue.

But a T-shirt created by New York University students, Sue Ngo and Nien Liam, could make the point more obvious than a government report. The shirt, which features either a picture of a heart or a set of lungs, uses a sensor built into the fabric to detect carbon monoxide in the surrounding environment. When the molecules are detected, the organ fills with blue veins.