Roadside air can be highly charged

A new study has found that there are far more charged particles beside busy roads than under high-voltage power lines.

A study by the Queensland University of Technology (QUT) researchers 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 researcher Rohan Jayaratne.

"However, people do not realise that a large number of charged particles in urban environments come from motor vehicle emissions," he added.

The researchers found that the concentration of charged particles was higher especially when the traffic included heavy-duty diesel trucks.

"I think it is something to consider when new housing estates are planned."

Jayaratne said 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.

Therefore, it is not surprising that several studies have demonstrated a link between particulate pollution from exhaust fumes and adverse health effects.

"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'," Jayaratne said.

"We do not believe that ions are dangerous - the danger comes from the pollutants.

"The ions merely assist the particles to stick to the lungs. If there are no dangerous particles in the air to attach to the ions, there is no risk of ill health."

The study was published in the journal Science of the Total Environment.