Wood burners are being blamed for unhealthy levels of arsenic polluting some parts of the country.
GNS Science has released statistics on air pollution in advance of the Wellington Regional Council's report next week.
It says the concentration of arsenic in the air of Hastings, Wainuiomata in Lower Hutt and Henderson in west Auckland has reached up to twice the recommended limit.
Lead researcher Perry Davy says the high levels are a consequence of people using copper-chrome-arsenic treated timber in wood burners.
Arsenic levels peak during the winter and the burning of treated timber is banned by regional councils.
Hawke's Bay Regional Council's senior scientist of air quality says it is pushing an educational campaign to stop its use.
However, Kathleen Kozyniak says more needs to be done to stamp our the burning of treated wood and she would like to see government support.
Perry Davy says there is also concern that ash from treated timber is being used to fertilise gardens, potentially poisoning homegrown produce.
National Poison Centre toxicologist Michael Beasley says he is not concerned about the levels of arsenic detected.
"The levels are really very low levels and I don't see it as being of any concern - certainly not in the short term. The levels are hundreds of times lower, for example, than exposure standards for workplaces."
Dr Beasley said the guideline limit for arsenic outside is 5.5 nanograms per cubic metre, compared with 10,000 nanograms for workplaces.
However, GNS Science says that is comparing apples with oranges, as the workplace measure is based on an eight-hour shift and the environmental one is based on 24-hour exposure.
