Air quality in Hastings twice exceeded national pollution standards over the weekend.
The average level of very small particles in the air over Hastings, measured at St John's College, was five and three micrograms per cubic metre of air above the acceptable level of 50mg on both Saturday and Sunday.
Air quality rules are set under the National Environmental Standards and allow up to an average of 50mg of PM10 (Particulate Matter smaller than 10 microns) over a 24-hour period.
Hawke's Bay Regional Council air quality scientist Dr Kathleen Kozyniak said a combination of cold weather, not much wind and poor heating choices caused the breaches.
The readings were bad for everyone's health, she said.
"The particles have been linked to health issues and diseases including lung cancer and heart problems," Kozyniak said.
"The smaller they are, they get further into your system.
"What would help is for anyone using their burners to burn dry wood and nothing else. If you're burning treated timber, rubbish or wet wood, you're making our air dirty."
The Hawke's Bay region had three air pollution exceedances last year, and just one the year before.
Hawke's Bay Regional Council is targeting no more than one exceedance per year by September 2020.
Regional Council Sustainable Homes programme manager Mark Heaney said he was disappointed.
"About 87 per cent of the problem comes from domestic fires.
"We know there are some non-compliant fires that have yet to be replaced but even if the fire is compliant, trying to burn green or wet wood results in smoke that is an unhealthy nuisance.
"Where there's smoke, there's a fire that's not burning efficiently so your money is going up in smoke rather than heating your home," Heaney said.
Heaney said air quality had improved by 54 per cent in Napier and Hastings since 2009.
"But we've still got a way to go. I really encourage people to use our Sustainable Homes programme to replace a smoky fire with clean heating."
The council programme offers support to replace non-compliant wood burners across Hawke's Bay to help fund warmer, drier and healthier homes.
It also includes a Good Wood scheme in partnership with approved dry wood sellers.