Fitness trackers can tell you a lot about your body — your heart rate, your steps, even your REM cycles. Now, they can potentially track the environment around you, helping users understand the impact our surroundings have on their health. Researchers at Rutgers University have developed a wristband that tests the air around it for harmful particles. Users can access and analyze the data via a companion smartphone app, or even send the results to their doctor when they’re miles away from the office. While the wristband looks more like a science experiment than an everyday wearable right now, its inventors believe the technology could be added onto existing smart watches, providing the person wearing it with valuable information that’s not currently at their fingertips. “It’s like a Fitbit but has a biosensor that can count particles, so that includes blood cells, bacteria and organic or inorganic particles in the air,” said Mehdi Javanmard, senior author of the study and assistant Rutgers professor, in a press release.