3 Auckland Region
Air quality monitoring in Auckland dates back to 1964 when TSP and lead monitoring commenced at the Global Environmental Monitoring (GEMs) site in Penrose and at a site in Mt Albert. Additional monitoring at the Penrose GEMs site included sulphur dioxide (SO2) and smoke monitoring in 1975, NOx in 1987, PM10 in 1994 and PM2.5 in 1997. Monitoring of smoke and SO2 was discontinued during 2000. A second Auckland GEMs monitoring site was established in 1975 in Mt Eden, initially measuring lead and TSP, with the additions of NOx in 1991 and PM10 and PM2.5 in 1997.
The seven-day average TSP data from Auckland suggests some decrease in TSP concentrations since the 1970s, particularly at the Penrose monitoring site (Figure 3.1). The extent to which this reflects reductions in the PM10 component is uncertain.
Figure 3.1: The seven-day average TSP concentrations measured at Penrose and Mt Albert, Auckland since 1964
3.1 Monitoring sites and methods
Details of the air quality PM10 monitoring sites within the Auckland region up until December 2001 are shown in Table 3.1. These include a number of industrial and traffic monitoring sites as well as the Henderson, Takapuna, Mt Eden and Manukau residential sites.
Table 3.1: Ambient air quality monitoring sites for PM10 in Auckland
View table of ambient air quality monitoring sites (large table)
3.2 PM10 concentrations
Table 3.2 summarises the PM10 concentrations measured at the Auckland residential ambient air quality monitoring sites until December 2001. The table shows that exceedences of the 24-hour average guideline value occur at Takapuna (1997) and Henderson (1999). 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 would have occurred.
Because the proportion of days monitored at most sites is low, annual average results for some years and sites have not been reported owing to potential errors associated with limited sampling. For this report, a reporting criterion for annual averages of 15% has been used. The sample error associated with this is around 12%. Data indicates some annual average guideline value exceedences in Henderson and Mt Eden. Although the annual average concentrations for Takapuna using the TEOM method are below the annual average guideline value, this method tends to under-report PM10 concentrations relative to the required gravimetric method. Section 13.1 estimates the impact of the TEOM monitoring method on reported 24-hour and annual average concentrations. Data for Manukau are excluded because of potential inaccuracies associated with the optical monitoring method.
Figures 3.2 and 3.3 show the percentage of measured 24-hour average PM10 concentrations within the air quality categories at "residential neighbourhood" monitoring sites in Auckland. These figures show that the majority of concentrations are within the acceptable and good air quality categories for PM10. Figures 3.4 and 3.5 show the percentage of measured 24-hour average PM10 concentrations within the air quality categories at the Penrose "industrial dense" and the Khyber Pass "traffic peak" monitoring sites. Both the annual and 24-hour average guideline values have been breached at these sites.
Table 3.2: Summary of PM10 concentrations at Auckland residential ambient monitoring sites
Figure 3.2: The percentage of measured 24-hour average PM10 concentrations within air quality categories at Henderson and Mt Eden, Auckland
Figure 3.3: The percentage of measured 24-hour average PM10 concentrations within air quality categories at Takapuna, Auckland
See
figure at its full size (including text description).Figure 3.4: The percentage of measured 24-hour average PM10 concentrations within air quality categories at Penrose, Auckland
See figure at its full size (including text description).
Figure 3.5: The percentage of measured 24-hour average PM10 concentrations within air quality categories at Khyber Pass, Auckland
See figure at its full size (including text description).
