The ongoing blaze at the SkyCity convention centre is taking a toll on people's health in the central city. Thick smoke has choked the streets for 24 hours, causing hazy air and a strong smell of fireworks and burning plastic.
Aucklanders and people staying in the central city have reported headaches and coughs on social media, and Mayor Phil Goff told The Breeze he's suffering from stinging eyes and a sore throat after spending time near the blaze.
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NIWA's leading air quality researcher Dr Guy Coulson says the danger comes from how small the particles are.
New Zealand's air quality standards go by the concentration of PM10 - solid and liquid airborne particles with a diameter of less than 10 micro metres. These microparticles are small enough to make their way into the lungs and bloodstream, where they can do serious damage.
If a cubic metre of air features a higher concentration of pollutant particles than 50 micrograms over 24 hours, it's deemed a health hazard.
Auckland's CBD currently has a high chance of exceeding acceptable PM10 levels, Coulson told Newshub.
"Close to the fire, it could well exceed the limit."
The health risks of exposure to high levels of pollution are alarming - strokes and heart attacks become more likely, and those with respiratory illnesses like asthma could experience much worse symptoms.
The good news is that a one-off exposure like the SkyCity fire is unlikely to result in any long-term problems. It's people who are regularly breathing in harmful particles over a long period of time that are more likely to develop cancer and other serious illnesses.
Some people have taken to wearing masks around the central city, which Coulson says won't do much to filter out harmful small particles but might give wearers a sense of added security.
"All I can say is it won't make it any worse."
He says Aucklanders should be out of the woods as soon as the fire's out, as strong winds will disperse the smoke fairly quickly. However he wants people to remember that while clouds of dark smoke are easy to avoid, harmful particles are less so.
"Just because you can't see it doesn't mean nothing's there."
Coulson advises those living or working in the CBD to follow Auckland Regional Public Health Service's advice to keep windows closed and turn external air conditioning off to avoid bringing smoke inside. But his number one tip: "Simply don't go there."
Anyone with concerns for their health is urged to call Healthline on 0800 611 116 or seek other medical assistance.