Hastings' smoke pollution has seen the city breach national rules for the first time this year.
On Monday the average level of very small particles in the air over Hastings, measured at St John's College, was seven micrograms per cubic metre above the acceptable level of 50mg.
Hawke's Bay Regional Council air quality scientist Dr Kathleen Kozyniak said the small particles in the air are dangerous to the community's health.
"The high-pressure system we experienced last week combined with an increase in outdoor burning, domestic fires, low temps and not much wind all contributed to this exceedance.
"Everyone using their burners needs to burn dry wood and nothing else, and anyone who is permitted to burn outside must only burn dry vegetation, untreated timber and paper.
"If you are burning treated timber, rubbish, or wet wood, you're making our air dirty."
Air-quality rules are set under a National Environmental Standard and allow for one annual exceedance up to an average of 50mg of PM10 (Particulate Matter smaller than 10 microns) over a 24-hour period.
"We had one exceedance last year, three the year before, and we want to get to no more than one exceedance per year by September 2020," Dr Kozyniak said.
Regional council chair Rex Graham said every fire contributed to the recurring winter issue.
"No one thinks that their fire will be a problem, but it all adds up.
"I'm concerned that we're poisoning our air on a daily basis during the coldest months, and causing serious harm to our community. I see how many outdoor fires are being lit every day and I'm getting sick of it."
The council's sustainable homes programme manager, Mark Heaney, said he was disappointed to see the exceedance.
"While we've made big gains in improving our air quality over 10 years with improvements of 54 per cent in Napier and Hastings, we've still got a way to go.
"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 creates 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."
The regional council offers the sustainable homes programme with support to replace non-compliant wood burners across Hawke's Bay to help fund warmer, drier and healthier homes.
This also includes a Good Wood scheme in partnership with approved dry wood sellers.