Large pieces of plastic can break down into nanosized particles that often find their way into the soil and water. Perhaps less well known is that they can also float in the air. It's unclear how nanoplastics impact human health, but animal studies suggest they're potentially harmful. As a step toward better understanding the prevalence of airborne nanoplastics, researchers have developed a sensor that detects these particles and determines the types, amounts and sizes of the plastics using colorful carbon dot films.