A survey of smoke emissions from woodburners in Hawke's Bay shows a positive change in behaviour by householders.
The regional council's healthy-homes manager, Megan Rose, says that in 2005 domestic heating generated almost 90% of the smoke in Napier and Hastings.
Five years later there's been a noticeable reduction, Ms Rose says, because people are replacing their old, inefficient burners with other forms of heating.
She says it's a positive trend towards meeting the National Environmental Standards for emissions by 2018.
But Ms Rose says that, owing to climatic factors during the winter, the level of smoke in the Hastings airshed exceeded the national standard on 15 days compared with only three days in Napier.