It was also important to clean chimneys and flues at least once a year, she said.
"If the glass on the front of your wood burner is coated in 'gunk' it means you are not burning your fire hot enough."
Mrs Hawthorne said that buying good quality firewood can be expensive and when families are trying to keep their home warm there can be a temptation to use whatever wood is at hand, including off-cuts of treated timber from building sites.
"Most construction timber in New Zealand uses pinus radiata which is typically treated with toxic chemicals such as chromated copper arsenic (CCA). "Because of the toxicity of CCA the burning of treated timbers is banned in New Zealand," she said.
"Burning treated timber releases toxic fumes into the air and poses a health risk to anyone who may breathe the contaminated air."
Mrs Hawthorne said using dry, untreated wood is especially relevant in Taumarunui, which is located in an "air shed" that traps the pollution under an "inversion layer".
"The people most at risk from smoke pollution are those with existing respiratory conditions, such as asthma or bronchitis, babies and young children, diabetics and the elderly.
"In order to minimise air pollution it is important that people using fires only burn dry, untreated wood that has been split properly," she said.
"Banking up a fire with wood and damping it down overnight does not add significant warmth but greatly increases air pollution."
"The best option is to keep a supply of kindling and dry wood handy to re-start the burner in the morning."
