Carbon monoxide is known as the “silent killer” because it’s colorless, odorless, tasteless, and extremely dangerous. Take it from someone who has experienced the symptoms of carbon-monoxide poisoning; it’s a frightening experience. “Warning Signs,” a high-tech T-shirt that visualizes ambient pollution, is a wearable alarm you can take with you. Designed by Nien Lam and Sue Ngo, two graduate students from New York University, the shirt features a heart or pair of lungs. Pink at first, the faux-organs flash blue veins when sensors detect above-average levels of carbon monoxide, whether it’s from traffic, smokers, or a faulty heating system at home.