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GEMS/AMIS Air Quality Monitoring Programme Annual Report 2006

1 Summary

2 Introduction

3 Air Pollutants Monitored

4 Ambient Air Quality Guidelines and Standards

5 Monitoring Sites

6 Methods

7 Results and Discussion

7 Results and Discussion

7.1 Site performance and quality assurance

Valid data and data capture rates for NO₂, SO₂, CO, and PM₁₀ from the Greers Road, Burnside site were below 90% for the month of May due to air conditioning problems. During November and December valid NO₂, SO₂, and CO data were also below 90% as the sampling lines fell inside the PVC housing. Annual valid NO₂, SO₂, and CO data were also less than 90% for 2006.

At Gavin Street, Penrose valid NO₂, and SO₂ data were below 90% for the month of June due to analyser faults and a power outage. Low valid SO₂ data was also recorded in July and August due to motor problems and communication faults. However, annual valid data for these pollutants were greater than 90% for 2006.

Continuously monitored pollutant’s instrument performance during 2006 was generally very good, with all sites having annual data capture rates well over 90%. However, valid data and data capture rates for TSP at the St Albans site were less than 90% due to a faulty pump that was replaced in June 2006. Overall site performance is shown in Table 3 below, based on 10‑minute averages for continuously monitored data. Percent data capture is the per cent of total instrument availability. Per cent valid data is defined as the per cent valid data following quality assurance adjustments.

Table 3: Percentage valid and capture data 2006

View percentage valide and capture data 2006 (large table).

7.2 Carbon monoxide (CO) 2006

CO was monitored at Greers Road, Burnside. One-hour and eight-hour averages have been calculated from 10-minute averages recorded by the instruments.

The maximum results and their dates are described below.

Results are given in Figures 6 to 9.

At Greers Road, Burnside during the 12-month period there were no exceedances of the ambient air quality one-hour guideline (30 mg/m3). However, there was one exceedance of the eight-hour National Environmental Standard (10 mg/m3) on 10 June 2006. Charts analysing this exceedance are described in Section 7.9. The NES allow for one CO eight-hour exceedance in a 12-month period.

7.3 Nitrogen oxides (NO₂ and NO) 2006

The maximums for NO₂ and their dates for each site are described below.

Nitrogen dioxide results are in Figures 10 to 15 (Kowhai), 16 to 21 (Gavin Street), and 22 to 27 (Burnside).

There were no exceedances of the NO₂ ambient air quality one-hour standard (200 µg/m³) or the 24-hour guideline (100 µg/m³) during 2006 at any site in Auckland or Christchurch.

7.4 Sulphur dioxide (SO₂) 2006

Sulphur dioxide was monitored at Gavin Street, Penrose and Greers Road, Burnside. One-hour and 24-hour averages have been calculated from 10-minute averages recorded by the instruments.

The maximums for SO₂ and their dates for each site are described below.

Results for Gavin Street, Penrose are shown in Figures 28 and 29 and Greers Road, Burnside is shown in Figures 30 and 31. There were no exceedances of the SO₂ ambient air quality one-hour standard (350 µg/m³) or the 24-hour guideline (120 µg/m³) during 2006 at any site.

7.5 Volatile organic compounds (VOC) January–December 2006

Monitoring of VOCs was conducted at four sites, Kowhai Intermediate School, Kingsland; Gavin Street, Penrose; Greers Road, Burnside; and Coles Place, St Albans. VOC monitoring utilises passive sampling badges, exposed over a three-month period. A set of results for each 2006 quarter are shown in Tables 4 to 7. See monitoring method in section 4.

The benzene guideline is 10 µg/m³ as an annual average, with an average value of 3.6 µg/m³ to be achieved by 2010. The 2006 six-month and 12-month averages are described below.

Table 4: VOC results (January–March 2006)

View VOC results (January - March 2006) (large table).

Table 5: VOC results (April–June 2006)

View VOC results (April–June 2006) (large table)

Table 6: VOC results (July–September 2006)

View VOC results (July–September 2006) (large table)

Table 7: VOC results (October–December 2006)

View VOC results (October-December 2006)

7.6 PM₁₀ 2006

PM₁₀ is monitored at Greers Road, Burnside; Gavin Street, Penrose; and Kowhai Intermediate, Kingsland sites, using Thermo FH62-C14 Beta Gauges, and are included in this report. Twenty-four-hour averages have been calculated from 10-minute averages recorded by the instruments. All PM₁₀ data is reported at standard temperature and pressure (0°C and 101.3 kPa).

The maximums for PM₁₀ and their dates for each site are described below.

There were no exceedances of the ambient air quality standard (50 µg/m³) at Gavin Street, Penrose or Kowhai Intermediate, Kingsland during the 12-month period.

At Greers Road, Burnside, there were 21 exceedances of the 24-hour standard. Each exceedance and the date are listed in Table 8 below. Charts describing 24-hour averaged data for 2006 for each site are shown in Figures 32 to 33 (Kowhai), 34 to 35 (Gavin Street), and 36 and 37 (Burnside). As there were exceedances at the Christchurch site, more data analysis was carried out in Section 7.9. All exceedances occurred over the winter period, a time when wood burning is widely used to heat homes. Cold winter conditions strongly influence air pollution in the region especially in calm conditions. All 21 exceedances occurred in cooler months between mid-May and July 2006.

Table 8: Greers Road, Burnside PM₁₀ exceedances of the daily NES 2006

Note: National Environmental Standard for PM₁₀ = 50 µg/m³

7.7 Total suspended particulates (TSP) 2006

TSP is measured as a seven-day average from, Gavin Street, Penrose; Kowhai Intermediate, Kingsland; and Coles Place, St Albans. Maximum results are shown in the table below.

There were no exceedances of the Ministry of Health guideline of 60 µg/m³ at any site. The data from each site is described in Figures 1 and 2 below.

Missing data information for 2006 at Coles Place, St Albans is as follows:

• earlier in the year (February to March), samples ran over seven days and were invalid

• mid-2006, the pump broke down in May and was replaced in July

• at the end of the year samples were missed over the Christmas period

• the other three data gaps were caused by technician error.

Figure 1: Auckland TSP seven-day average 2006

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Figure 2: Auckland TSP seven-day average 1994–2006

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Figure 3: Christchurch TSP seven-day average 2006

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Figure 4: Christchurch TSP seven-day average 2002–2006

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7.8 Lead (Pb) June–August 2006

Lead is measured from seven-day averaged TSP samples to derive a three-month average. The results are described in the Table below. Figure 5 provides moving three-month averaged lead data between January 1996 and September 2000 when lead monitoring was performed on a monthly basis. From this point lead continued to be monitored over a three-month period (June to August) annually.

No site exceeded the three-month average guideline for lead (0.2 µg/m³).

Figure 5: MFE lead three-month average results 1996–2006

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Figure 6: MFE Burnside CO one-hour fixed average January–December 2006

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Figure 7: MFE Burnside CO one-hour fixed average 1 January 2003–31 December 2006

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Figure 8: MFE Burnside CO eight-hour rolling average January–December 2006

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Figure 9: MFE Burnside CO eight-hour rolling average 1 January 2003–31 December 2006

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Figure 10: MFE Kowhai NO₂ one-hour fixed average January–December 2006

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Figure 11: MFE Kowhai NO₂ one-hour fixed average 1 January 2004–31 December 2006

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Figure 12: MFE Kowhai NO₂ 24-hour fixed average January–December 2006

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Figure 13: MFE Kowhai NO₂ 24-hour fixed average 1 January 2004–31 December 2006

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Figure 14: MFE Kowhai NO₂ and NO one-hour fixed average January–December 2006

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Figure 15: MFE Kowhai NO₂ and NO 24-hour fixed average January–December 2006

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Figure 16: MFE Gavin Street NO₂ one-hour fixed average January–December 2006

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Figure 17: MFE Gavin Street NO₂ one-hour fixed average 1 January 1997–31 December 2006

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Figure 18: MFE Gavin Street NO₂ 24-hour fixed average January–December 2006

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Figure 19: MFE Gavin Street NO₂ 24-hour fixed average 1 January 1997–31 December 2006

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Figure 20: MFE Gavin Street NO₂ and NO one-hour fixed average January–December 2006

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Figure 21: MFE Gavin Street NO₂ and NO 24-hour fixed average January–December 2006

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Figure 22: MFE Burnside NO₂ one-hour fixed average January–December 2006

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Figure 23: MFE Burnside NO₂ one-hour fixed average 1 January 2003–31 December 2006

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Figure 24: MFE Burnside NO₂ 24-hour fixed average January–December 2006

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Figure 25: MFE Burnside NO₂ 24-hour fixed average 1 January 2003–31 December 2006

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Figure 26: MFE Burnside NO₂ and NO one-hour fixed average January–December 2006

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Figure 27: MFE Burnside NO₂ and NO 24-hour fixed average January–December 2006

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Figure 28: MFE Gavin Street SO₂ one-hour fixed average January–December 2006

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Figure 29: MFE Gavin Street SO₂ 24-hour fixed average January–December 2006

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Figure 30: MFE Burnside SO₂ one-hour fixed average January–December 2006

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Figure 31: MFE Burnside SO₂ 24-hour fixed average January–December 2006

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Figure 32: MFE Kowhai PM₁₀ 24-hour fixed average January–December 2006

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Figure 33: MFE Kowhai PM₁₀ 24-hour fixed average 1 January 2004–31 December 2006

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Figure 34: MFE Gavin Street PM₁₀ 24-hour fixed average January–December 2006

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Figure 35: MFE Gavin Street PM₁₀ 24-hour fixed average 1 January 2003–31 December 2006

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Figure 36: MFE Burnside PM₁₀ 24-hour fixed average January–December 2006

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Figure 37: MFE Burnside PM₁₀ 24-hour fixed average 1 January 2003–31 December 2006

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7.9 Analysis of exceedances

7.9.1 Exceedances at Greers Road, Burnside

A 72-hour period, 9–11 June 2006, has been chosen as a typical example of winter diurnal trends coinciding with PM₁₀ and CO exceedances, to describe the relationship between pollution levels and meteorological conditions. Figures 38 and 39 provide an example of the typical diurnal trend in PM₁₀ and CO respectively during this period. Figures 40 to 42 present the meteorological conditions that influence the diurnal trend. It is apparent when comparing wind speed (Figure 40) with PM₁₀ and CO concentrations that low wind speeds coincide with PM₁₀ and CO peaks and conversely higher wind speeds coincide with low PM₁₀ and CO concentrations. Reduced air mixing, caused by low wind speeds results in poor dispersion of pollution, while an unstable atmosphere caused by high wind speeds, is conducive to pollution dispersion. Wind rose analysis (Figure 42) shows the predominant wind was from a north north east direction with 32% calm.

Low temperatures, often coinciding with still atmospheric conditions, can cause temperature inversions. This can contribute to higher PM₁₀ and CO concentrations being measured as pollution is trapped at ground level. A comparison of temperatures measured at 1.5 and 10m (Figure 44) does not indicate the presence or absence of a temperature inversion as the inversion height may be greater than 10m, however, a diurnal trend is apparent. As the temperature drops during the evening, Christchurch residents light their heating appliances causing PM₁₀ and CO levels to peak just before midnight. As the fires die down and the atmosphere becomes more unstable toward morning, concentrations of PM₁₀ and CO drop off.

A pollution rose for the same 72-hour period (Figures 43 and 44) describes the relationship between wind directions, wind speed and pollutant concentrations with 0% calm. Both pollution roses show no obvious patterns. This suggests that the incidents are related to meteorological conditions such as temperature inversions.

Figure 38: MFE Burnside PM₁₀, 10-minute fixed average 9–11 June 2006

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Figure 39: MFE Burnside CO, 10-minute fixed average 9–11 June 2006

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Figure 40: MFE Burnside wind speed, 10-minute fixed average 9–11 June 2006

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Figure 41: MFE Burnside ambient temperature, 10-minute fixed average 9–11 June 2006

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Figure 42: MFE Burnside pollution rose, wind speed 10-minute average 9–11 June 2006

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Figure 43: MFE Burnside pollution rose, PM₁₀ 10-minute average 7–9 June 2006

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Figure 44: MFE Burnside pollution rose, CO 10-minute average 7–9 June 2006

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