Air quality in Hawke’s Bay is generally good, but air quality is a concern in our main urban areas, as Hastings and Napier can suffer smoke pollution from wood burners used for home heating. Hawke’s Bay Regional Council (HBRC) has researched the causes of the air quality problems in Napier and Hastings which led to a programme to reduce smoke pollution by upgrading home heating and insulation. HBRC reports publicly on PM10 levels each month during winter, and in its State of the Environment reporting.
Most urban air quality issues happen during late autumn and winter, when cold still days follow a southerly moving through the region. An inversion layer forms over the Heretaunga Plains at night, when air is colder close to the ground and warmer further up (the reverse of normal temperature patterns). This traps the smoke from home heating wood burners close to the ground until the air warms up or the wind picks up.
The impacts from PM10 air pollution on the population of Hawke’s Bay in 2006 were estimated as: more than 100,000 restricted activity days; 54 hospital admissions; 113 premature adult deaths; and social costs of $411 million annually (Kuschel et al., 2012).
The National Environmental Standards require no more than one day (24 hour period) a year when PM10 is more than 50 microns per cubic metre. Napier was required to meet this low threshold from 1 September 2016 and Hastings from 1 September 2020. PM10 concentrations in Napier and Hastings have dropped to meet both of the deadlines for compliance with the NES.
The community has responded well to HBRC’s Heatsmart programme which offers homeowners in Napier and Hastings financial assistance through grants and loans to upgrade insulation and heating. The programme also certifies suppliers of guaranteed dry wood which also improves air quality, and has a strong education component.
HBRC also used mobile MicroVol monitoring equipment to check air quality in smaller urban areas. Havelock North, Wairoa, Greenmeadows, Waipukurau, Waipawa and Ahuriri have all been monitored. The mobile unit is in place generally for one year to assess whether PM10 is likely to be a problem or not in areas where no monitoring data exists. This information is not available on LAWA but is made publicly available through HBRC’s State Of The Environment monitoring reports.
As well as home heating, other sources of air pollution in Hawke’s Bay include -
• industry - emissions are assessed through consent monitoring and pollution reporting
• traffic – periodic monitoring of contaminants at roadside locations is undertaken for a period of 8 weeks in Napier and Hastings.
• rural burning – burning of orchard redevelopment material or diseased plant material is permitted with in the airshed under specified wind conditions. Advice on outdoor burning and other air quality issues can be found at https://www.hbrc.govt.nz/environment/air-quality/info-sheets/.