Arrowtown’s air this winter was the cleanest it’s been in five years.
A new report from Otago Regional Council says Arrowtowners suffered 25 foul-air days – or “exceedances”, as ORC labels them – the lowest since winter records began in 2006 and the lowest of nine Otago towns monitored.
ORC air quality scientist Deborah Mills reports that of those nine towns, only Arrowtown “exhibits some fairly consistent downward movement”.
In three of the past five years, foul air polluted Arrowtown on nearly 40 days each winter.
Mills attributes the air improvement to a combination of ORC’s “Clean Heat Clean Air” subsidy programme and this winter’s fortuitous weather.
One hundred Arrowtown homes have now taken advantage of ORC subsidies to upgrade heating systems and insulation-reducing emissions by about 10 per cent overall, she says.
The other factor this winter was neutral weather about half-way between La Nina and El Nino conditions, the scientist says.
May and June were the warmest on record, followed by relatively unsettled, milder and windier conditions with sharp cold snaps during July and August.
As a result, “temperature inversions” weren’t as strong and were also at a greater height, reducing the pollutant effect, Mills reports.
Mills notes ORC has a target of 2013 for Otago to comply with a national environment standard of just one foul-air day per year per town.
Arrowtown’s foul-air days are “overwhelmingly due to emissions from domestic solid fuel burners”, Mill says.
Another 600 local homes will need heating conversions before compliance can be met, she adds.