Scientists Track Air Pollution’s Immediate Health Effects Using Wearables

Over a month-long period, participants wore Fitbit smartwatches and completed frequent mood surveys while their smartphone GPS data tracked environmental exposures to heat and pollutants such as nitrogen dioxide, particulate matter, and sulfur dioxide. This approach allowed researchers to observe real-time physiological and emotional responses linked to varying environmental conditions.

The study, conducted by researchers at The City University of New York and published in JMIR Formative Research, involved Sameera Ramjan and Melissa Blum as co-first authors, alongside Rung Yu Tseng, Katherine Davey, Duke Shereen, and senior author Yoko Nomura. It represents the first known integration of wearable technology, ecological momentary assessment, and continuous GPS tracking to measure immediate health effects from environmental exposures.

Data revealed that higher heat and nitrogen dioxide exposure correlated with altered heart rate variability, an indicator of stress recovery capacity. Meanwhile, increased sulfur dioxide exposure was associated with heightened feelings of nervousness and hopelessness. Unexpectedly, greater heat exposure corresponded with reduced self-reported sadness, a finding the researchers suggest may relate to increased outdoor activity and social interaction during warmer periods.

“People move through many different environments each day, and this approach lets us capture that in real time,” said Ramjan, a doctoral student at the CUNY Graduate Center. “We were struck by how quickly the data revealed patterns—changes in heart rate variability, shifts in mood—that lined up with where participants had been and what they were exposed to.”

Blum, a medical student at the Icahn School of Medicine at Mount Sinai, emphasized the complexity of the relationship between environmental conditions and physiological and emotional responses. She noted that combining wearable sensors, GPS data, and real-time surveys enables the creation of individualized exposure profiles that move with participants, contrasting with traditional reliance on stationary monitors or home addresses.

Senior author Nomura, a distinguished psychology professor at CUNY Graduate Center and Queens College with an appointment at the Icahn School of Medicine, described the study as a proof of concept demonstrating how consumer technology can integrate with environmental epidemiology. “It’s a small pilot, but it demonstrates an integration between consumer technology and environmental epidemiology that could open the door to personalized approaches for preventive medicine,” Nomura stated.

The research team identified areas for system improvement, such as enhancing ease of use and participant adherence, which have been incorporated into a subsequent, larger NIH-supported study. This ongoing research focuses on the effects of prenatal and current environmental exposures on adolescent brain development and mental health.

As extreme heat and air pollution continue to rise, disproportionately impacting vulnerable populations including children, pregnant individuals, the homeless, and socioeconomically disadvantaged groups, this technology could have significant public health implications. Children’s brain development and behavior may be particularly susceptible to environmental exposures.

Beyond research applications, the system holds potential for clinical use by enabling real-time monitoring of environmental exposures to inform medical decisions for patients affected by heat or poor air quality. Nomura cautioned that the findings are preliminary but underscored the importance of improved exposure measurement for public health protection.

The study, titled “Feasibility of Integrating Wearable Devices and Ecological Momentary Assessment for Real-Time Environmental Exposure Estimation: Proof-of-Concept Study,” was published on 8 May 2026 in JMIR Formative Research. It received funding from a Professional Staff Congress–City University of New York (PSC-CUNY) research grant.