Extract While smoking is the prominent risk factor for chronic obstructive pulmonary disease (COPD), environmental exposures play a significant etiologic role in both smokers and never-smokers in the United States (U.S.) 1, 2. Furthermore, COPD rates vary among population subgroups with different exposure profiles 3. Reported associations between ozone exposure and COPD have been inconsistent 4, and there is limited understanding of the interrelationships between ozone, atmospheric conditions, and the air exposome, which partly explain subgroup differences. Additionally, whether ozone exposure consistently below the current U.S. National Ambient Air Quality Standard (70 ppb average/8 h) is associated with increased COPD risk remains unclear, especially among subgroups. We addressed these knowledge gaps using data from the All of Us Research Program (AoU), a prospective mega-cohort of >864 000 U.S. adults 5. Here, we investigated the complexities surrounding the respiratory effects of ozone and provide greater precision into which subgroups might be more susceptible to COPD, which could inform risk stratification and targeted exposure reduction efforts.
Lo et al. (2026) studied this question.