People living near the country's busiest motorway are raising concerns about the effect it's having on their long term health.

A University of Canterbury team has been studying air quality in two South Auckland communities, which motorways cut through carrying over 120,000 vehicles a day.

The research found asthma and allergies are common.

People living near the motorways say the smell of smoke and fumes, and road noise stops them going outside.

The study says there's extra concern for people who are unemployed or retired, because they're more likely to be exposed for longer.