Media Release

8 May 2014

Hawke’s Bay Air Quality Science Informs WHO Review

Hawke’s Bay is doing as well as, if not better than, many other towns and cities in New Zealand in terms of air quality, says Hawke’s Bay Regional Council scientists in response to a report from the World Health Organisation.

The United Nations public health arm has released a report of outdoor air quality in 1600 cities across 91 countries. Subsequent news reports have stated that many smaller centres have worse air quality than metropolitan Auckland.

The World Health Organisation (WHO) used figures supplied by the Ministry for the Environment based on data supplied by regional councils. These figures are the annual mean concentrations of fine particulate matter, which are particles smaller than 10 micrometres per cubic metre of air (ie PM10).

HBRC air scientist Dr Kathleen Kozyniak says that annual mean PM10 concentrations for both Napier and Hastings are lower than the MfE’s Ambient Air Quality Guideline value of 20 micrograms per cubic metre. They rank similarly to Auckland at 14 and 15 micrograms per cubic metre respectively.

Dr Kozyniak says that HBRC was advised last year that WHO would be collecting data, and councils had the opportunity to verify their monitoring information.

“On the whole there has been a pleasing decrease in PM10 concentrations in our two cities since monitoring began in 2005/6,” says Dr Kozyniak.

“From 2010 to 2012 we saw Hastings concentrations drop from 17 to 15 micrograms per cubic metre and Napier’s from 15 to 14 micrograms per cubic metre. Having said that, there was a blip upward in concentrations last year in both cities for a number of possible reasons, such as the light winds we had last winter. I’m aware there was a similar pattern in other NZ centres’ air quality too.”

Dr Kozyniak says that weather plays a part in air quality.

“Hawke’s Bay’s winters may be blessed with days of fine blue skies and calm conditions in winter but, although they cheer the heart, these are conditions which trap smoke close to the ground. Some of the centres listed in the news report have windier and wetter conditions which help to clear the air.”

Hawke’s Bay Regional Council has conducted emissions inventories (2005 and 2010, another is due next year) which indicate that domestic fire emissions contribute more than 90% of the wintertime concentrations of PM10.

HBRC’s Heatsmart Programme Manager, Mark Heaney, says that council’s Heatsmart scheme for upgrading older model wood burners to more efficient modern burners or heat pumps means that people can expect to see PM10 concentrations progressively decrease.

“The quality of the air in Napier and Hastings during winter still needs to improve and we all have to work towards that. It has been encouraging to advise a lot of people over the past few months on the choices they can make for home heating and how to take advantage of the Council’s funding assistance package.”

Below are graphs for Napier and Hastings average winter only concentrations, as compared to the annual average quoted by WHO. These graphs are adjusted to take account of the variation in weather between winters. Overall the trend is downward, but with a blip last year.

Napier

Hastings

Note – micrograms per cubic metre are shown as µgm-3

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