The study found that within 10 metres of a freeway, charged particles were up to 15 times more concentrated than beneath high-voltage power lines.
"Although the effects of ions and charged particles generated by high-voltage power lines on human health is still open to conjecture, there has been a lot of attention on increased exposure due to expanding power networks in urban residential areas," said Rohan Jayaratne from Queensland University of Technology.
"However what people do not realise is that a large number of charged particles in urban environments come from motor vehicle emissions," said Jayaratne.
"This was especially the case when the traffic included heavy-duty diesel trucks and I think it is something to consider when new housing estates are planned," Jayaratne said.
He said that while there was no evidence that breathing in air ions was a health risk, approximately one-half of the fine particles that we inhale during normal breathing are deposited in our lungs.
"This link is stronger in urban environments where the majority of particulate matter comes from motor vehicles which are known to be harmful. Diesel emissions contain a range of toxic chemicals and have recently been classified as 'probably carcinogenic to humans'," he said.
"I feel these findings may have potentially important implications for the atmosphere, climate, urban planning and particularly for human health," Jayaratne added.
The study was published in the journal Science of the Total Environment.