Dr Bennett, of the university's Wellington campus, was among more than 560 graduands, mainly in health sciences, who graduated in person from the university, in a ceremony at the Dunedin Town Hall on Saturday.
Research for her doctorate in public health focused on "the sources and childhood respiratory health effects of nitrogen dioxide in homes".
"It's certainly an important, world-first study," Dr Bennett said.
The research is based on the largest intervention study involving unflued domestic gas heating and is part of a wider Housing and Health Research Programme led by public health researcher Prof Philippa Howden-Chapman.
The national trial involved 409 households - including 85 in Dunedin - that had a child with asthma and used unflued gas heaters or plug-in electric heating. More effective, non-polluting heaters were installed in half the homes.
Elevated nitrogen dioxide levels made breathing more difficult for children with asthma, Dr Bennett said.
Homes using unflued gas heaters were found to have more than three times the level of nitrogen dioxide in living rooms than homes without unflued gas heaters.
Homes using gas stove-tops also had elevated nitrogen dioxide levels.
Nitrogen dioxide in the living room was associated with greater hospital admission, and greater daily reports of asthma and other upper respiratory tract symptoms.
Homes with heat pumps, flued gas heating or enclosed wood burners were found to have lower levels of nitrogen dioxide in living rooms and children's bedrooms.
Children in the intervention group also had less parent-reported poor health, reduced asthma symptoms, fewer reports of colds and flu, and fewer visits to doctors and chemists than children in the control group, she said.
