Long-term PM 2.5 exposure and leukemia risk from childhood to early adulthood: A nationwide longitudinal cohort study with time-varying exposure analysis.

Annual PM 2.5 concentrations were assigned to all 226 inland districts in South Korea using mean predictions from a machine learning-based ensemble model.

Among 384,606 individuals aged 0-18 at enrollment, 272 developed leukemia during follow-up, including 83 who were diagnosed after the age of 18 years.

The cohort's average annual PM 2.5 concentration was 29.6 μg/m 3 (standard deviation: 3.1).

Long-term PM 2.5 exposure was associated with increased leukemia incidence in this national cohort.