Personalized air quality monitoring and respiratory health in moderate and severe asthma: Findings from a six-month observational study

INTRODUCTION: Asthma affects over 339 million people worldwide, contributing substantially to morbidity, reduced quality of life, and premature mortality. Air pollution is a major risk factor, but stationary monitors lack the resolution to capture individual exposure. This study aimed to (i) evaluate the feasibility of integrating personalized air quality monitoring with digital health tools in patients with moderate-to-severe asthma; (ii) explore preliminary associations between pollutant exposures and respiratory outcomes; and (iii) characterize interrelations among symptoms, spirometry, wearable-derived physiology, and inhaler use. METHODS: Thirteen adults with moderate-to-severe asthma participated in a six-month observational study using a digital monitoring ecosystem. This combined wearable sensors for physiological and air quality data, daily symptom reporting via smartphone, and spirometry assessments. Outdoor pollution data were obtained from the nearest fixed-site monitoring station. RESULTS: Personal sensors revealed highly variable exposures that diverged from ambient measurements, particularly for nitrogen dioxide, which showed greater variability and more frequent exceedances of World Health Organization thresholds. Self-reported symptoms and inhaler use were strongly correlated. However, no consistent associations were observed between pollution exposure and health outcomes, including symptoms or spirometry results, even when time-lagged effects were considered. CONCLUSION: These findings highlight the limitations of relying on ambient stations to assess exposure in asthma research and underscore the importance of individualized monitoring. Combining wearable pollution sensors with continuous symptom tracking and remote lung function testing is feasible and patient-centered. This integrative approach may inform precision medicine strategies and improve individualized asthma management.