Pedestrians and workers on one of New Zealand's busiest streets are at serious risk of being exposed to black carbon, a pollutant that can cause health issues.
A study by Auckland Council found increasing air pollution levels on Queen Street - which sees about 10 million pedestrians per year and 4000-5000 vehicles per day -- linked to diesel emissions from old buses, ferries, trucks and ships.
High buildings on Queen Street are also though to reduce air flow, resulting in concentrated pollution closer to the ground, according to an article by air quality scientist Nick Talbot published recently in the Auckland Council Research and Evaluation Unit's quarterly newsletter.
"Over the past decade air pollution concentrations have fallen, largely due to cleaner fuel, engine improvements and changes in traffic management," the article states. "More recently, however, this downward trend has reversed, with concentrations on Queen Street now on the rise once again."
The concentrations are over three times higher than Canadian cities and two times over major cities in Europe and the United States, the report found.
And it's not a good sign for Aucklanders' health.
"Black carbon consists of very small ultra-fine particles...not much larger than viruses," Talbot explained. "These can travel deep into lung tissue, into the bloodstream and then become deposited in the heart or brain tissue with detrimental health impacts."
While the major culprit appears to be buses, they are essential to the CBD so reducing their numbers isn't feasible, he concluded. But continuing to retrofit the city's fleet with cleaner fuel systems or replacing vehicles with electric alternatives will reduce the hazardous pollution, he said.