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

11 West Coast and Southland Regions

Limited monitoring of PM₁₀ has been carried out in the West Coast and Southland regions. However, some smoke monitoring has been carried out in Greymouth in 1994 and 1995, in Reefton in 1995 and in Invercargill in 1983, 1985, 1986 and from 1990 to 1997. Smoke monitoring has also been carried out in the Southland areas of Winton and Wyndham in 1974, in Bluff in 1985 and in Mataura in 1996 and 1997. A monitoring strategy to measure PM₁₀ concentrations in urban areas on the West Coast is underway with initial monitoring in Greymouth during 2001. The Southland region is currently preparing a monitoring strategy to assess concentrations of PM₁₀ within the region. Monitoring for PM₁₀ in that region is scheduled to commence during winter 2003.

11.1 Monitoring sites and methods

Details of the ambient air quality PM₁₀ monitoring site in Greymouth are shown in Table 11.1. This is a residential neighbourhood site that measures concentrations of PM₁₀ using high-volume gravimetric sampling.

Table 11.1: Ambient air quality monitoring site for PM₁₀ in the West Coast region

Area	Location	Duration	Site classification	Monitoring method
Greymouth	49 Palmerston Street	May-August 2001	Residential neighbourhood	High-volume sampler
Westport	Derby Street	31 May - 3 September 2002	Residential neighbourhood	High-volume sampler

11.2 PM₁₀ concentrations

Figure 11.1 shows that concentrations of PM₁₀ measured in Greymouth during 2001 did not exceed the ambient air quality guideline values on any of the 21 sampling days during the winter monitoring period. The maximum measured 24-hour average PM₁₀ concentration of 46 µgm^-3 is within the alert air quality category.

Concentrations of PM₁₀ measured in Greymouth during 2001 did not exceed the ambient air quality guideline values on any of the 21 sampling days during the winter monitoring period. The maximum measured 24-hour average PM₁₀ concentration of 46 µgm^-3 is within the alert category. In Westport, the ambient air quality guideline value was breached on around 9% of the days monitored (Figure 11.1). Summary statistics for both monitoring sites are shown in Table 11.2.

Table 11.2 includes an indication of the number of days PM₁₀ concentrations exceeded the 24-hour average PM₁₀ guideline value of 50 µgm^-3. For Westport, this shows the number of exceedences that were measured and an estimate of the number that may have been measured if monitoring had been carried out on all days. This estimate is shown in the table as the equivalent number of exceedences.

Table 11.2: Summary of PM₁₀ concentrations at ambient monitoring sites in Greymouth and Westport

Area	24-hour maximum	24-hour 99.5 percentile	Annual average	% of days monitored	Days > 50 µgm-3	% of winter days guideline was exceeded
Greymouth	46	45	n/a	6%	0	0%
Westport	56	55.4	n/a	8%	3 measured 12 equivalent*	9%

* This is an estimate of the number of days PM₁₀ concentrations may have exceeded the guideline value if monitoring had been carried out on all days during winter (May to August inclusive). It is extrapolated from the number of measured exceedences and the number of days when monitoring did occur.

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