Methamphetamine has been detected in the air in central Auckland by a first-of-its-kind study done in New Zealand and Australia.

Traces of the class A drug along with nicotine, caffeine and tetrahydrocannabinol (THC) were caught by filters at a pollution monitoring site on Customs St near the bottom of Queen St according to an analysis done by scientists from Waipapa Taumata Rau - University of Auckland.

The study revealed meth concentrations were higher than in overseas cities such as Barcelona.

Airborne drug concentrations had spiked in the week leading up to the Christmas holidays and also over New Year’s Eve.

Master of Science student Olivia Johnson and Dr Joel Rindelaub, a research fellow in the School of Chemical Sciences, revealed the largest concentration of meth detected was 104 picograms (a picogram is one-trillionth of a gram) per cubic metre of air.

The average for 10 samples over five weeks was 24.8 picograms per cubic metre.

“Assuming an active dose of 5 milligrams and 16 cubic metres of air inhaled per person each day, it would take an individual over 8000 years to inhale an active dose,” the scientists wrote in a paper published in the journal Atmospheric Pollution Research.

University of Auckland research fellow in the School of Chemical Sciences, Dr Joel Rindelaub. Photo / Michael Craig

However, Rindelaub said the results weren’t as concerning but they highlighted that “we really don’t know as much as we should about what’s in the air that we breathe”.

The study also showed that nicotine had the highest average concentration of the four drugs at 4.91 nanograms (a nanogram is one billionth of a gram) per cubic metre, a level lower than in many cities overseas.

Caffeine, likely from sources including steaming takeaway coffees, and THC, from people smoking cannabis, were both detected at lower average concentrations than in studies elsewhere.

Rindelaub and Johnson said airborne monitoring of drugs could complement wastewater analyses which were carried out for the likes of cocaine, fentanyl, heroin, methamphetamine and MDMA to track drug consumption in communities around the country.

They said it would be easier to assess the effectiveness of policies such as restrictions on tobacco products with the technique.

“Caffeine concentrations, meanwhile, seem to correlate with urban pedestrian counts, suggesting a potential proxy for urban activity.”

A PhD candidate and air quality scientist at Mote Ltd, Hamish Patel, and Associate Professor Gordon Miskelly also worked on the study, which used liquid chromatography with tandem mass spectrometry to analyse samples collected from December 7, 2020 to January 11, 2021.

In a separate study published in December last year Rindelaub and other scientists revealed there were microplastics swirling in Auckland’s air that are equivalent to more than 3 million plastic bottles falling from the sky every year.

“The problem is indoors, too,” Rindelaub had said.

After testing the air in a university lecture theatre where he was delivering a TEDx talk on pollution, Rindelaub found indications of polyester, nylon and PVC.

“Over 3300 premature deaths per year are related to air pollution in Aotearoa,” he said.

- The study, the first of its type in Oceania, was only looking for methamphetamine, nicotine, caffeine, and THC, leaving unknown what other drugs may be floating around.