Measures to improve Otago's winter air pollution to set
standards have failed in all but two of the region's towns,
triggering a review of the Otago Regional Council's
management of the problem.
The council is to review its air quality management strategy
after monitoring last winter confirmed many towns in the
region would not meet the National Environmental Standard for
Air Quality (NESAQ).
Under the standard, towns are allowed to exceed the daily
standard - of 50mcg per cu m of airborne pollutant, with a
particle size below 10 microns - only three days a year by
2016 and then one day a year by 2020.
Alexandra breached the standard 47 times last winter, Milton
42 (once as high as 139mcg) and Cromwell 33.
The council's own daily standard of 50mcg, exceeded only once
a year - set in the Regional Plan: Air in 2006 - was to be
complied with by last September but only central Dunedin and
Palmerston met the target.
Council air quality scientist Deborah Mills said, in a report
to be considered at tomorrow's technical committee meeting,
several initiatives had been undertaken to achieve compliance
but analysis of the monitoring results showed progress had
''There are numerous challenges to meeting the NESAQ in
Otago. These cut across social, economic, cultural,
logistical, technological and the greatest climatological
There had been some improvements, she said. Last year,
Arrowtown had its lowest winter average, 30 micrograms per cu
m of air, since records began in 2006; Clyde's maximum PM10
levels (very small particles) had decreased by 30% and
Mosgiel's 10 highest days dropped 15% on the long-term
''However, it is unlikely that Alexandra and Arrowtown will
meet the NESAQ.''
Those two towns, along with Milton, experienced some of the
worst air quality in the country and represented about 7% of
Otago's population, she said.
About 20% of those households had taken part in the council's
Clean Heat, Clean Air compliant heating scheme, resulting in
an estimated 10%-20% reduction in emissions.
The towns were also climatically challenged, in terms of air
quality, as they were situated at the base of hills or dams
and, in very cold and still winter conditions, there was
little air movement for smoke dispersion.
Preliminary work on new projections indicated that even if
the rate of change was able to be sustained in
Alexandranational air quality standards would not be achieved
''Sustaining the current rate of change is unlikely, as well,
given that the central government subsidy for domestic
heating appliances has ended.''
Other challenges included finding quality alternative
heating, the cheapness of coal, relative to the increasing
costs of electric or gas heating, and the logistics of being
able to source or store dry wood.
Despite this, a large majority of people in Otago lived in
towns with relatively good air quality, she said.
Dunedin had experienced its best air quality year since 2006.
It has met national guidelines two years in a row.
Mosgiel had only a ''handful'' of high-pollution days this
It took five consecutive years of meeting the guidelines for
a town to be considered not polluted.