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A calm and chilly winter has exposed the challenge faced by local councils battling to reduce chimney smoke pollution before 2013.
Environment Ministry air quality guidelines say there should be a maximum of 50 pm10 (fine particle emissions) per cubic metre over a 24 hour period.
In 2013 the guidelines will be enforced and there will be severe consequences for breaches as they are seen as a significant health risk to the public.
Many towns and cities throughout the country have breached those levels many times already this winter.
In Hawke's Bay, levels are already as bad as they were for the entire winter last year.
The vast majority of the problem has been put down to smoke from home fires being trapped in inversion layers during calm and cold weather.
The problem has been pronounced in Central Otago this year, with Alexandra alone recording dangerous levels 18 times in June and 20 times in May.
Levels have commonly been between 75 and 150 as residents burn wood to keep warm and the smoke hovers in the air above on still days with nowhere to escape.
The climate and geography contributes to a similar problem in towns such as Cromwell, Arrowtown and Clyde, Otago Regional Council environmental scientist John Threlfall says.
"They need to heat their houses somehow and traditionally it has been by wood," he said.
"The smoke gets trapped in the inversion. It's the dispersion of the smoke which is the issue."
Mr Threlfall said pollution levels had been tracking down over the past few years but this year they had shot up again.
He said the council had plans to enforce the use of heat-pumps, gas or clean burning fires, but the latter could only be effective if dry wood was used.
Subsidies would also be made available for Community Card holders needing to do alterations in the Otago region.
Mr Threlfall said residents in the Central Otago towns where pollution was an issue would not be able to emit more than 1.5 grams of particles per kilogram of wood burnt after January 1, 2012.
Any new burners installed would have to meet requirements of 0.7g, which was a tough target to meet.
He said data proved smoke pollution posed genuine health risks and the 2013 national target shouldn't be seen as central government bureaucracy.
Nelson also faces a battle, having exceeded the guideline 15 times at two sites last month, but only narrowly.
Nelson City Council put the burden of improving air quality on ratepayers at the start of the year by banning open fires.
The council's air quality policy planner Richard Frizzell said pollution levels were trending down.
He said the push for clean air included completely phasing out older burners by 2012 and offering financial assistance packages to those affected.
Mr Frizzell said some still flouted the rules and used open fires, but the council employed someone to keep an eye on the city's chimneys.
Despite publicity, some people were genuinely unaware of the rules and addressing the problem was a matter of the council explaining the situation, providing information about the incentives available and ensuring it didn't happen again.
"I would have to say there is a lot of public acceptance. When we proposed these rules in the air plan they weren't opposed or taken to court or challenged, which meant we were able to move on them quicker than other councils."
Environment Canterbury air and energy programme manager Linda Kirk said emissions rules were being rolled out across the region, with a particularly strict focus on Christchurch.
The council appears to have struck some public resistance though, with its air plan being appealed in the Environment Court.
Ms Kirk said there were 23 appellants Canterbury-wide on various aspects of the plan, which would delay attempts to get it enacted.
While there have been guideline breaches in Christchurch this winter, Timaru has been the district's worst offender with 15 breaches in the past month.
Breaches beyond 2013 will force local authorities to have to decline the renewal of air discharge consents - something that would not only affect industry, but also the likes of schools and hospitals.
"While it's tough, underlying it all is that we are dealing with a serious health problem," Mr Frizzell said.
"If we put the politics to one side, the national environmental standard is driven by the need to improve air quality."
- NZPA
