Air Quality, Improved Results for Hawke’s Bay
17 October 2012
Air Quality, Improved Results for Hawke’s Bay
Napier had much clearer air this winter and in Hastings the overall level of pollution has dropped noticeably.
Hawke’s Bay Regional Council scientists and the Heat Smart programme team reported the positive results to Councillors this week.
“It’s great to see air quality improving across our cities as residents make an effort to upgrade their home heating and insulation, but we can’t ease up as there’s still a way to go to get consistently clear air in winter,” says Councillor Kevin Rose, Chairman of HBRC’s Environment and Services Committee.
The National Environment Standard for Air Quality sets a standard of 50 micrograms per cubic metre of PM10 (particulate matter, mostly in smoke from household fires) averaged over 24 hours.
In Napier the NES has typically been exceeded 3 to 5 times a year at the Marewa Park site. This year, for the first time since continuous monitoring began, there was not a single exceedance. The highest concentration was 49.4 micrograms per cubic metre, just below the NES limit of 50 micrograms.
In Hastings the NES has been exceeded up to 28 times one year, but this year only 10 times. The overall concentration of PM10 was also lower this year; the highest level recorded - 60.4 micrograms per cubic metre - was the lowest winter maximum since continuous monitoring began at the Mayfair site.
This year HBRC installed a monitoring site at Awatoto where the NES was exceeded on one occasion in July - the concentration reached 51.3 micrograms per cubic metre.
HBRC also carried out a PM10 screening monitoring in Waipukurau from June 2011 to June 2012.
“This was to see if permanent monitoring would be necessary in the town, but for the most part air quality was good or excellent,” said Dr Kathleen Kozyniak, HBRC’s senior scientist, air and climate.
She told Councillors that on most monitoring days in Waipukurau PM10 was less than 16.6 micrograms per cubic metre, and the highest concentration recorded was 41 micrograms.
Over the past year HBRC has also commissioned additional work to investigate the air pollution issue.
Golder Associates worked on air quality modelling to estimate the amount of reduction in emissions needed to meet the National Environmental Standard (NES) for PM10 and to investigate the movement of PM10 between and within airsheds. This research showed that very little of the PM10 in Napier’s air zone originates in Hastings and vice versa. However within airsheds, dispersal is significant with smoke drifting into areas, especially from the south.
Environet Ltd assessed whether improvements to domestic heating would be enough to achieve the NES. Air quality and climate are closely linked, as wind and cold temperatures have a role in dispersing pollutants and providing the conditions which lead to the need for home heating.
Both HBRC and Environet Ltd take winter weather into account when comparing PM10 concentrations from year to year. This is done by taking the average of PM10 concentrations only on days when the NES is most likely to be exceeded, otherwise known as “normalised” concentrations, and is a widely accepted practice amongst Regional Councils.
Environet Ltd assessed that, in both Napier and Hastings, the normalised winter PM10 concentration in 2012 was lower than the previous 6 years. They also concluded that the rules and incentives currently in place through HBRC’s Heat Smart programme should be sufficient to achieve the NES.
The main focus of HBRC’s Heat Smart programme is the phasing out and replacement of domestic fires that do not meet current national emission standards. To meet exceedance targets for PM10 it has been estimated that HBRC would need to financially support the replacement of 10,000 domestic fires by 2020. The fire replacement target for Heat Smart up to 30 September 2012 was 1094 and the actual number of replacements taking up HBRC grants/loans has been 1515, and the number accessing EECA subsidies has been 2637.
Home insulation incentives and the Dry Wood Scheme also contribute to the reduction of PM10. Since 2009, 766 homes have taken up HBRC financial assistance for insulation. “Compared to national trends for insulation and clean heat uptake through EECA schemes, Hawke’s Bay continues to perform well, with 23% of houses in the Napier and Hastings airsheds accessing funding, compared to a national average of 13%,” said Heat Smart Manager Mark Heaney.
HBRC Agenda Item is available here.