Children are particularly vulnerable to environmental tobacco smoke exposure: Evidence from biomarkers of tobacco-specific nitrosamines, and oxidative stress.

•Children had a significantly lower ability to detoxify NNK than adults.•Urinary total NNAL:cotinine ratio could inform on the ETS exposure source.•In children, THS might be a more important source of NNK exposure than SHS.•Children have a higher risk of ETS health effects, e.g., oxidative stress.