Bay cities enjoy better air quality

People taking the chance to upgrade home heating and insulation systems are being credited for cleaner winter air conditions reported over Hastings and Napier this year.

The Hawke's Bay Regional Council's scientists and Heat Smart programme staff said the overall level of air pollution had dropped noticeably when marked against the National Environment Standard (NES).

It set a standard of no higher than 50 micrograms per cubic metre of PM10, or particulate matter, mostly in smoke from household fires, averaged over 24 hours.

The results of the winter's air-quality tests were presented to the council's environment committee on Wednesday.

In Napier, the standard had typically been exceeded three to five times a year at the Marewa Park site.

This year, for the first time since continuous monitoring began, it was not exceeded.

The highest concentration was 49.4 micrograms per cubic metre, just below the standard limit of 50 micrograms.

In Hastings, the standard had been exceeded up to 28 times in a year but this year it happened only 10 times.

The overall concentration of PM10 was also lower this year; the highest level recorded was 60.4 micrograms per cubic metre, the lowest winter maximum since continuous monitoring began at the Mayfair site.

This year regional council installed a monitoring site at Awatoto, where the standard was exceeded once in July, the concentration reaching 51.3 micrograms per cubic metre.

It also carried out a PM10 screening monitoring in Waipukurau from June 2011 to June 2012 and planned another in Waipawa over the next year. Regional council senior scientist Dr Kathleen Kozyniak said this was to see if permanent monitoring would be necessary in the towns but for the most part air quality was good or excellent.

On most monitoring days in Waipukurau, PM10 was less than 16.6 micrograms per cubic metre, and the highest concentration recorded was 41 micrograms.

Councillor Tim Gilbertson, from Central Hawke's Bay, could not see the point of monitoring in Waipawa because it was a small town and not likely to exceed the standard limit.

"I am sceptical ... There is no problem in Waipukurau or Waipawa and I can't see this is a good use of ratepayer money."

The Heat Smart programme aimed to phase out and replace domestic fires which did not meet national emission standards.

To meet exceedance targets for PM10 it has been estimated the regional council would need to financially support the replacement of 10,000 domestic fires by 2020. The fire-replacement target for Heat Smart up to September 30, 2012, was 1094 and the actual number of replacements taking up regional council grants and loans had been 1515, and the number accessing Energy Efficiency and Conservation Authority (EECA) subsidies had been 2637.

Home-insulation incentives and the regional council's "dry wood scheme" also contributed to the reduction of PM10. Since 2009, 766 homes had taken up financial assistance for insulation.