Wearable devices track real-time health effects of pollution and heat

As climate change drives more frequent extreme heat and worsening air pollution, researchers are seeking better ways to understand how these exposures affect health in real time. A new pilot study led by researchers at The City University of New York demonstrates the feasibility of combining wearable devices, smartphone location data, and real-time surveys to capture individuals' environmental exposures and their immediate physical and emotional effects.

The newly published study, "Feasibility of Integrating Wearable Devices and Ecological Momentary Assessment for Real-Time Environmental Exposure Estimation," appears in the journal JMIR Formative Research. The study was co-authored by Sameera Ramjan and Melissa Blum (co-first authors), Rung Yu Tseng, Katherine Davey, and Duke Shereen, with Yoko Nomura as senior author.

"People move through many different environments each day, and this approach lets us capture that in real time," said Ramjan, a doctoral student in the CUNY Graduate Center Psychology program. "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."

For the study, participants wore Fitbit smartwatches for roughly a month while completing short mood surveys known as ecological momentary assessments several times a day. Researchers combined these data with smartphone location tracking to estimate exposure to heat and air pollutants such as nitrogen dioxide, particulate matter, and sulfur dioxide based on where participants spent time throughout the day.

The findings suggest that this integrated approach is not only feasible but also revealing. On days with higher exposure to heat and nitrogen dioxide, participants showed changes in heart rate variability, a marker of the body's ability to recover from stress. Higher exposure to sulfur dioxide was associated with increased feelings of nervousness and hopelessness. Interestingly, higher heat exposure was linked to lower self-reported sadness, a counterintuitive finding that may reflect seasonal patterns in outdoor activity and social engagement during warmer weather, underscoring the need for larger studies to disentangle these effects.

"Even in a small pilot, we could see that the relationship between environmental conditions and people's physiological and emotional responses is more complex than traditional methods can capture," said Blum, a medical student at the Icahn School of Medicine at Mount Sinai. "By combining wearable sensors, GPS data, and real-time surveys, we're able to build individualized exposure profiles that move with people throughout their day. That's a real shift from relying on stationary monitors or home addresses."

"To our knowledge, this is the first study to combine wearable devices, ecological momentary assessment, and continuous GPS tracking to measure environmental exposures and their immediate health impacts," said senior author Nomura, a distinguished professor of Psychology at the CUNY Graduate Center and Queens College with an appointment at the Icahn School of Medicine at Mount Sinai. "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."

The pilot study also identified areas for improvement, including simplifying the system and increasing participant adherence - lessons that have already been incorporated into the next phase of the research. Building on these findings, Nomura's team is now applying the refined system to a larger, National Institutes of Health (NIH)-supported study examining how prenatal and current environmental exposures affect brain development and mental health in adolescents.

The work comes at a critical moment. Exposure to extreme heat and air pollution is increasing, with disproportionate impacts on vulnerable populations, including children, pregnant individuals, people experiencing homelessness, and those with lower socioeconomic status. Children are particularly at risk because environmental exposures can have lasting effects on brain development and behavior.

Beyond research, the approach could have clinical applications. Real-time environmental exposure monitoring could one day help clinicians make more informed decisions about patient care, particularly for individuals with conditions sensitive to heat or air quality.

"This is still early-stage work, and we're cautious about reading too much into a small sample," Nomura said. "But improving how we measure exposure is a critical step toward protecting public health, and these results give us confidence that the approach can scale."

The study was supported by a Professional Staff Congress–City University of New York (PSC-CUNY) research grant.

Source:

The Graduate Center, CUNY

Journal reference: