Monitoring of PM₁₀ in New Zealand

• Foreword
• Acknowledgements
• Executive Summary
• 1 Introduction
• 2 Monitoring Methods for Particles in New Zealand
• 3 Auckland Region
• 4 Waikato Region
• 5 Bay of Plenty Region
• 6 Taranaki and Northland Regions
• 7 Gisborne and Hawkes Bay Regions
• 8 Wellington Region
• 9 Nelson, Tasman and Marlborough Districts
• 10 Canterbury Region
• 11 West Coast and Southland Regions
• 12 Otago Region
• 13 Trends in PM₁₀ Concentrations in New Zealand
• References
• About the Ministry

7 Gisborne and Hawkes Bay Regions

Air quality monitoring for PM₁₀ in the Gisborne and Hawkes Bay regions is limited to the towns of Gisborne and Napier. In each of these areas data are available for one ambient air quality monitoring site and one background air quality monitoring site.

7.1 Monitoring sites

Details of the four ambient air quality PM₁₀ monitoring sites within the Gisborne and Hawkes Bay regions are shown in Table 7.1. These include one background PM₁₀ monitoring site in Gisborne and one regional monitoring site in Napier.

Table 7.1: Ambient air quality monitoring sites for PM₁₀ in Gisborne and Hawkes Bay

Area	Location	Duration	Site classification	Monitoring method
Gisborne	Oates Road	From April 1993 to December 2000	Residential neighbourhood	High-volume
Gisborne	McDonalds Road	From November 1993	Background - special (rural)	High-volume
Napier	Nelson Park	From July 2001	Residential neighbourhood	High-volume
Napier	Guppy Road	February 1996 to June 1999	Residential Regional	High-volume

7.2 PM₁₀ concentrations

Concentrations of PM₁₀ measured in Napier suggest that 24-hour average PM₁₀ concentrations may exceed the air quality guideline values on around 13% of the winter days (Table 7.2). In Gisborne one exceedence of the guideline value was measured on 28 October 1998 and coincided with northwest winds and elevated wind speeds of around 8 ms^-1 on average. Dusts and/ or sea spray are potential sources under these types of conditions. Extrapolations of this measured data show that if monitoring was undertaken every day during the winter months, it is likely that more exceedences of the guideline value may have occurred. For Napier, this extrapolation was based on the proportion of the amount of data available for the period from May to August inclusive, but for Gisborne because the exceedence was not seasonal, the extrapolation was based on the data available for the whole year.

Figures 7.1 and 7.2 show the percentage of measured 24-hour average PM₁₀ concentrations within the air categories at the sites in Gisborne and Napier. These graphs show that the majority of concentrations were within the good air quality categories for all sites.

Table 7.2: Summary of PM₁₀ concentrations at ambient monitoring sites in Gisborne and Napier

View table of PM₁₀ concentration at ambient monitoring sites in Gisborne and Napier (large table)