Concern for her five children prompted an Auckland mother to study for a PhD focusing on how vapes are marketed.
Lucy Hardie has been in full-time study at the University of Auckland since 2014, when all of her kids were under the age of 10 - and was capped on Thursday.
She also has a Masters in Public Health and Bachelor of Health Sciences.
Her interest in vaping began as young people started to take it up in 2018, before the industry was regulated.
And her kids - now in their teens - are proving to be a useful research tool, right in the thick of an age group greatly affected by vaping.