Scientists are testing air quality at two schools in Auckland to see whether exhaust emissions from traffic could have long-term effects on children's health.
The National Institute of Water & Atmospheric Research says findings from similar research in Los Angeles show children living within 0.5km from a freeway grew up with reduced lung capacity.
Air samples have already been gathered from two schools close to motorways - Waterlea Public School near Mangere Bridge, and Wymondley Road School in Otara.
NIWA's says it first has to determine how the air quality compares to other countries like Australia, before undertaking any research.
Two more schools will be surveyed in central Auckland, next year.
