Biomonitoring evidence of smoke-free policy effectiveness in Korea: success against secondhand smoke but emerging residual exposure challenges

Our findings provide biomonitoring evidence that Korea's smoke-free policies effectively reduced SHS exposure, but the effects have plateaued in recent years, revealing emerging challenges to mitigate THS exposure and indoor e-cigarette use. Evidence-based smoke-free strategies reflecting real-world smoking behaviours are needed to ensure equitable protection of people who do not smoke across different exposure settings and to sustain a smoke-free environment.