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Executive Summary

Air quality monitoring for particles in New Zealand dates back to the 1960s when monitoring sites for total suspended particulate (TSP) were established in Christchurch and Auckland. A more extensive monitoring network was established in the 1980s with measurements of smoke carried out in many of the regions. In 1988, the first monitoring site measuring PM10 was established in Christchurch in the inner city suburb of St Albans. The 1990s saw increased monitoring of PM10 throughout the country and by 2001, concentrations of PM10 had been monitored in most regions.

These data for PM10 measurements in New Zealand have been collated and are presented in this report based on the monitoring methods outlined in the Good Practice Guide for Air Quality Monitoring and Data Management and the 24-hour and annual average ambient air quality guideline values in the Ambient Air Quality Guidelines - 2002 Update (MfE, 2000; MfE and MoH, 2002).

Air quality monitoring data supplied by regional councils indicates that exceedences of the guideline value of 50 µgm-3 (24-hour average) have occurred in:

  • Auckland
  • Hamilton
  • Tokoroa
  • Taupo
  • Whangarei
  • Rotorua
  • Upper Hutt
  • Lower Hutt
  • Masterton
  • Otaki
  • Napier
  • Wainuiomata
  • Nelson
  • Richmond
  • Whakatane
  • Timaru
  • Ashburton
  • Blenheim
  • Kaiapoi
  • Oamaru
  • Christchurch
  • Mosgiel
  • Arrowtown
  • Rangiora
  • Dunedin
  • Cromwell
  • Alexandra.
  • Balclutha
    

The sampling regimes in many locations are insufficient to determine a reliable annual average PM10 concentration estimate. Of the 15 areas where sufficient PM10 data were available, breaches of the annual average guideline value of 20 µgm-3 were found in Tokoroa, Nelson, Christchurch, Auckland, Timaru and Kaiapoi.

An extrapolation of existing PM10 data collected using the Tapered elemental operating microbalance (TEOM®) sampling method was carried out to determine the equivalent concentrations if an alternative approved sampling method had been used. These data indicated that additional breaches of the annual average PM10 guideline value may have occurred in Hamilton, Te Kuiti, Tauranga, Upper Hutt, Ashburton and Rangiora. The 24-hour average PM10 guideline value is also likely to have been breached in Te Kuiti.

The number of days the guideline value is breached varies from year to year and from location to location. In most areas these occur during the winter months and coincide with periods of low wind speed and temperature inversions. Exceptions include areas such as Gisborne, Otaki and Whangarei where guideline value breaches may have occurred as a result of sources such as sea spray, wind blown dust or localised industrial sources.

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