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Air GEMS/AMIS Air Quality -
Monitoring Programme: Annual Report 2007 Online version
7 Results and Discussion
7.1 Site performance and quality assurance
Overall site performance and explanations shown in table 3 below, based on 10-minute averages for continuously monitored data. Per cent of valid data (V) is defined as the per cent valid data following quality assurance adjustments. Per cent of captured data (C) is the per cent of total instrument availability.
All sampling was performed at all sites as planned during 2007, except at Kowhai, where the site was decommissioned in September. This was unavoidable due to redevelopment of the site and a new site is currently being investigated. Annual valid data rates were below 95 per cent at Greers Road, Burnside as the sample lines were found inside the PVC housing.
Continuously monitored pollutant’s instrument performance during 2007 was generally very good, and with the exception of Kowhai, all sites had annual data capture rates greater than 95 per cent.
Table 3: Percentage valid and capture data 2007
| Analyte | Site | Percentage valid data (V) and Percentage data capture (C) | |||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| January | February | March | April | May | June | July | August | September | October | November | December | Annual | |||||||||||||||
| V | C | V | C | V | C | V | C | V | C | V | C | V | C | V | C | V | C | V | C | V | C | V | C | V | C | ||
| CO | Burnside | 1.9a | 99.8 | 98.3 | 99.8 | 98.2 | 99.7 | 97.7 | 99.5 | 97.8 | 99.9 | 97.6 | 100 | 86.9d | 99.7 | 98.1 | 100 | 97.2 | 99.7 | 98.3 | 99.9 | 98.2 | 99.9 | 84.6i | 99.9 | 87.7 | 99.8 |
| NO2 | Penrose | 97.9 | 100 | 96.6 | 98.4 | 98.3 | 100 | 89.4c | 99.8 | 98.3 | 100 | 95.2 | 96.9 | 89.4f | 91.6f | 97.7 | 99.9 | 98.1 | 100 | 98.3 | 99.9 | 97.7 | 99.4 | 98.1 | 100 | 96.3 | 99.0 |
| NO2 | Burnside | 1.3a | 99.8 | 98.1 | 99.8 | 97.9 | 99.7 | 97.7 | 99.5 | 98.3 | 99.9 | 98.4 | 100 | 95.2 | 99.7 | 98.4 | 100 | 97.2 | 99.7 | 98.0 | 99.9 | 98.3 | 99.9 | 98.1 | 99.9 | 89.6 | 99.8 |
| NO2 | Kowhai | 97.8 | 100 | 98.2 | 100 | 98.2 | 100 | 97.4 | 100 | 88.0d | 100 | 97.7 | 100 | 98.5 | 100 | 95.2 | 100 | 14.5g | 15.0g | 0.0g | 0.0 g | 0.0 g | 0.0 g | 0.0 g | 0.0 g | 65.3 | 67.8 |
| SO2 | Penrose | 97.4 | 100 | 95.5 | 98.4 | 97.0 | 100 | 96.4 | 99.8 | 97.4 | 100 | 94.1f | 96.9 | 88.6f | 91.6f | 97.4 | 99.9 | 97.4 | 100 | 92.5 | 99.9 | 96.8 | 99.4 | 97.0 | 100 | 95.6 | 99.0 |
| SO2 | Burnside | 1.7a | 99.8 | 97.5 | 99.8 | 97.4 | 99.7 | 97.1 | 99.5 | 97.6 | 99.9 | 97.8 | 100 | 97.2 | 99.7 | 97.3 | 100 | 91.3h | 99.7 | 97.7 | 99.9 | 97.5 | 99.9 | 97.5 | 99.9 | 88.8 | 99.8 |
| PM10 | Burnside | 91.9 | 99.8 | 98.8 | 99.8 | 98.1 | 99.7 | 98.1 | 99.5 | 98.8 | 99.9 | 98.3 | 100 | 97.4 | 99.7 | 97.8 | 99.9 | 98.5 | 99.7 | 98.2 | 99.9 | 98.6 | 99.9 | 97.3 | 99.9 | 97.6 | 99.8 |
| PM10 | Kowhai | 98.7 | 100 | 99.1 | 100 | 98.9 | 100 | 99.0 | 100 | 99.0 | 100 | 98.8 | 100 | 99.8 | 100 | 99.7 | 100 | 14.7g | 15.0g | 0.0g | 0.0 g | 0.0 g | 0.0 g | 0.0 g | 0.0 g | 67.2 | 67.8 |
| PM10 | Penrose | 98.8 | 100 | 97.2 | 98.4 | 98.8 | 100 | 98.7 | 99.8 | 99.1 | 100 | 95.9 | 96.9 | 89.5f | 91.6f | 98.8 | 99.9 | 98.6 | 100 | 98.4 | 99.9 | 97.6 | 99.4 | 98.4 | 100 | 97.5 | 98.8 |
| VOC | Penrose | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| VOC | Burnside | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| VOC | St Albans | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| TSP | St Albans | 60b | 60b | 75b | 75b | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 60b | 100 | 100 | 100 | 75 b | 75 b | 88.5 | 92.3 |
| TSP | Penrose | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 |
| TSP | Kowhai | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 25g | 25g | 0g | 0 g | 0 g | 0 g | 0 g | 0 g | 69.2 | 69.2 |
| Lead | St Albans | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 100 | 100 | 100 | 100 | 100 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 100 | 100 |
| Lead | Penrose | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 100 | 100 | 100 | 100 | 100 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 100 | 100 |
| Lead | Kowhai | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 75e | 75e | 100 | 100 | 100 | 100 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | 92.3 | 92.3 |
Notes:
a Sample lines inside PVC housing
b Sampling error
c Analyser pump fault
d Analyser exchange failed
e Sample missing
f Power cut
g Site decommissioned
h Analyser swap and warm-up
i Analyser fault
7.2 Carbon monoxide (CO) 2007
CO was monitored at Greers Road, Burnside. One-hour and 8-hour averages have been calculated from 10-minute averages recorded by the instruments.
Summary statistics for CO and their dates are described below.
| Site |
Maximum 1-hour average (mg/m3) |
99.9 percentile 1-hour average (mg/m3) |
Maximum 8-hour average (mg/m3) |
99.9 percentile 8-hour average (mg/m3) |
|---|---|---|---|---|
| Greers Road, Burnside | 9.2 (6 August 23:00) |
6.3 | 5.5 (7 August 02:00) |
4.7 |
Carbon monoxide results are shown in figures 7 to 11.
At Greers Road, Burnside during the 12 month period there were no exceedances of the ambient air quality 1-hour guideline (30 mg/m3) or 8-hour National Environmental Standard (10 mg/m3).
7.3 Nitrogen oxides (NO2 and NO) 2007
Oxides of nitrogen were monitored at Gavin Street, Penrose, Kowhai Intermediate, Kingsland and Greers Road, Burnside. One hour and 24-hour averages have been calculated from 10‑minute averages recorded by the instruments.
Summary statistics for NO2 and their dates for each site are described below.
| Site |
Maximum 1-hour average (µg/m3) |
99.9 percentile 1-hour average (µg/m3) |
Maximum 24-hour average (µg/m3) |
99.5 percentile 24-hour average (µg/m3) |
|---|---|---|---|---|
| Gavin Street, Penrose | 88.4 (29 May 09:00) |
73.0 | 55.8 (27 June) |
50.0 |
| Kowhai Intermediate School, Kingsland | 81.4 (3 July 09:00) |
68.7 | 43.7 (4 July) |
42.7 |
| Greers Road, Burnside | 66.6 (19 July 20:00) |
56.6 | 38.1 (28 July) |
34.6 |
Nitrogen dioxide results are shown in figures 12 to 21 (Kowhai), 22 to 31 (Gavin Street), and 32 to 41 (Burnside).
There were no exceedances of the NO2 ambient air quality 1-hour standard (200 µg/m3) or the 24-hour guideline (100 µg/m3) during 2007 at any site in Auckland or Christchurch.
7.4 Sulfur dioxide (SO2) 2007
Sulfur 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.
Summary statistics for SO2 and their dates for each site are described below.
| Site |
Maximum 1-hour average (µg/m3) |
99.9 percentile 1-hour average (µg/m3) |
Maximum 24-hour average (µg/m3) |
99.5 percentile 24-hour average (µg/m3) |
|---|---|---|---|---|
| Gavin Street, Penrose | 43.2 (17 June 12:00) |
25.0 | 11.9 (19 June) |
10.1 |
| Greers Road, Burnside | 52.2 (1 March 08:00) |
31.4 | 13.8 (27 July) |
11.0 |
Results for Gavin Street, Penrose are shown in figures 42 to 46 and Greers Road, Burnside is shown in figures 47 to 51. There were no exceedances of the SO2 ambient air quality 1-hour standard (350 µg/m3) or the 24-hour guideline (120 µg/m3) during 2007 at any site.
7.5 Volatile organic compounds (VOC) January–December 2007
Monitoring of VOCs was conducted at four sites, Kowhai Intermediate School, Kingsland, Gavin Street, Penrose, Greers Road, Burnside, and Coles Place, Christchurch. VOC monitoring utilises passive sampling badges, exposed over a three-month period. A set of results for each 2007 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 2007 six-month and 12-month averages are described below. The benzene annual averages from all the sites are less than the AAQG 2002 guideline and are graphed in figure 1.
| Site |
Six-month average (January–June 2007) benzene (µg/m3) |
Six-month average (July–December 2007) benzene (µg/m3) |
2007 annual average benzene (µg/m3) |
|---|---|---|---|
| Coles Place, St Albans | 1.9 | 1.3 | 1.6 |
| Greers Road, Burnside | 1.8 | 1.3 | 1.5 |
| Gavin Street, Penrose | 1.3 | 0.8 | 1.1 |
| Kowhai Intermediate, Kingsland | 1.3 | 1.2 | 1.3 |
Table 4: VOC results (January–March 2007)
| January–February–March 2007 Analyte |
Limit of detection (µg/m3) |
Results (µg/m3) | |||
|---|---|---|---|---|---|
| Coles Place | Burnside | Gavin Street | Kowhai | ||
| Target VOCs | |||||
| ethanol | ND | ||||
| isopropyl alcohol | ND | ||||
| acetone | ND | ||||
| pentane | ND | ||||
| dichloromethane | ND | ||||
| butan-2-one | ND | ||||
| hexane | 0.5 | 0.5 | 0.7 | 0.6 | 0.7 |
| ethyl acetate | ND | ||||
| trichloromethane | ND | ||||
| 1,1,1-trichloroethane | ND | ||||
| n-butanol | ND | ||||
| benzene | 0.2 | 0.7 | 0.7 | 0.6 | 0.6 |
| 2-methylhexane | 0.5 | 0.6 | |||
| 2,3-dimethylpentane | ND | ||||
| 3-methylhexane | 0.5 | 0.5 | |||
| heptane | ND | ||||
| trichloroethene | ND | ||||
| propyl acetate | ND | ||||
| methylcyclohexane | ND | ||||
| 4-methylpentan-2-one | ND | ||||
| toluene | 0.2 | 4.0 | 3.3 | 5.2 | 4.6 |
| octane | ND | ||||
| tetrachloroethene | ND | ||||
| butyl acetate | ND | ||||
| ethylbenzene | 0.3 | 0.6 | 0.5 | 0.7 | 0.6 |
| m+p-xylene | 0.3 | 2.1 | 1.7 | 2.4 | 1.9 |
| styrene | ND | ||||
| o-xylene | 0.3 | 0.7 | 0.6 | 0.8 | 0.6 |
| nonane | ND | ||||
| alpha pinene | ND | ||||
| propylbenzene | ND | ||||
| 1,3,5-trimethylbenzene | ND | ||||
| beta pinene | ND | ||||
| decane | ND | ||||
| 1,2,4-trimethylbenzene | 0.6 | 0.8 | 0.7 | 0.9 | 0.8 |
| limonene | ND | ||||
| undecane | 0.7 | 0.8 | |||
| dodecane | ND | ||||
| tetradecane | ND | ||||
ND = Not detected.
Table 5: VOC results (April–June 2007)
| April–May–June 2007 Analyte |
Limit of detection (µg/m3) |
Results (µg/m3) | |||
|---|---|---|---|---|---|
| Coles Place | Burnside | Gavin Street | Kowhai | ||
| Target VOCs | |||||
| ethanol | ND | ||||
| isopropyl alcohol | ND | ||||
| acetone | ND | ||||
| pentane | 2.9 | 3.5 | 3.0 | ||
| dichloromethane | ND | ||||
| butan-2-one | ND | ||||
| hexane | 0.6 | 1.3 | 1.6 | 1.8 | 1.7 |
| ethyl acetate | 0.6 | 0.8 | 0.6 | ||
| trichloromethane | ND | ||||
| 1,1,1-trichloroethane | ND | ||||
| n-butanol | ND | ||||
| benzene | 0.3 | 3.1 | 3.0 | 2.0 | 2.1 |
| 2-methylhexane | 0.7 | 1.2 | 2.0 | 0.7 | 0.6 |
| 2,3-dimethylpentane | 0.7 | 1.8 | |||
| 3-methylhexane | 0.7 | 1.6 | 2.9 | 0.8 | 0.7 |
| heptane | 0.7 | 1.4 | 2.2 | 0.8 | 0.6 |
| trichloroethene | 0.6 | 1.1 | |||
| propyl acetate | ND | ||||
| methylcyclohexane | 0.7 | 3.6 | 9.9 | ||
| 4-methylpentan-2-one | ND | ||||
| toluene | 0.3 | 12.5 | 9.8 | 12.3 | 12.5 |
| octane | ND | ||||
| tetrachloroethene | ND | ||||
| butyl acetate | 0.6 | 0.7 | |||
| ethylbenzene | 0.4 | 1.9 | 1.5 | 2.0 | 1.9 |
| m+p-xylene | 0.4 | 5.6 | 4.3 | 5.8 | 5.2 |
| styrene | ND | ||||
| o-xylene | 0.4 | 2.6 | 1.9 | 2.3 | 2.0 |
| nonane | ND | ||||
| alpha pinene | 0.9 | 0.7 | |||
| propylbenzene | ND | ||||
| 1,3,5-trimethylbenzene | 0.7 | 0.8 | 0.7 | ||
| beta pinene | 0.9 | 1.1 | 0.8 | ||
| decane | 0.8 | 0.7 | |||
| 1,2,4-trimethylbenzene | 0.8 | 2.3 | 1.7 | 2.4 | 2.3 |
| limonene | ND | ||||
| undecane | 0.9 | 0.8 | |||
| dodecane | ND | ||||
| tetradecane | ND | ||||
ND = Not detected.
Table 6: VOC results (July–September 2007)
| July–August–September 2007 Analyte |
Limit of detection (µg/m3) |
Results (µg/m3) | |||
|---|---|---|---|---|---|
| Coles Place | Burnside | Gavin Street | Kowhai | ||
| Target VOCs | |||||
| ethanol | ND | ||||
| isopropyl alcohol | ND | ||||
| acetone | ND | ||||
| pentane | 2.3 | 3.0 | 2.7 | ||
| dichloromethane | ND | ||||
| butan-2-one | ND | ||||
| hexane | 0.5 | 1.2 | 1.6 | 1.1 | 1.3 |
| ethyl acetate | 0.5 | 0.5 | 0.8 | 0.5 | |
| trichloromethane | ND | ||||
| 1,1,1-trichloroethane | ND | ||||
| n-butanol | ND | ||||
| benzene | 0.2 | 2.2 | 2.2 | 1.1 | 1.5 |
| 2-methylhexane | 0.5 | 1.5 | 1.3 | ||
| 2,3-dimethylpentane | 0.5 | 1.1 | 0.9 | ||
| 3-methylhexane | 0.5 | 2.2 | 1.8 | ||
| heptane | 0.5 | 1.8 | 1.6 | ||
| trichloroethene | 0.5 | 1.3 | |||
| propyl acetate | ND | ||||
| methylcyclohexane | 0.5 | 2.2 | 1.7 | ||
| 4-methylpentan-2-one | ND | ||||
| toluene | 0.3 | 8.4 | 6.9 | 6.5 | 7.5 |
| octane | ND | ||||
| tetrachloroethene | ND | ||||
| butyl acetate | 0.5 | 0.5 | |||
| ethylbenzene | 0.3 | 1.3 | 1.1 | 1.0 | 1.2 |
| m+p-xylene | 0.3 | 4.5 | 3.6 | 3.9 | 4.2 |
| styrene | ND | ||||
| o-xylene | 0.3 | 1.7 | 1.4 | 1.3 | 1.4 |
| nonane | ND | ||||
| alpha pinene | ND | ||||
| propylbenzene | ND | ||||
| 1,3,5-trimethylbenzene | ND | ||||
| beta pinene | ND | ||||
| decane | ND | ||||
| 1,2,4-trimethylbenzene | 0.6 | 1.6 | 1.2 | 1.3 | 1.4 |
| limonene | ND | ||||
| undecane | 0.7 | 0.7 | |||
| dodecane | ND | ||||
| tetradecane | ND | ||||
ND = Not detected.
Table 7: VOC results (October–December 2007)
| October–November–December 2007 Analyte | Limit of detection (µg/m3) |
Results (µg/m3) | |||
|---|---|---|---|---|---|
| Coles Place | Burnside | Gavin Street | Kowhai | ||
| Target VOCs | |||||
| ethanol | ND | ||||
| isopropyl alcohol | ND | ||||
| acetone | ND | ||||
| pentane | ND | ||||
| dichloromethane | ND | ||||
| butan-2-one | ND | ||||
| hexane | 0.4 | 0.5 | 1.0 | 0.7 | 0.9 |
| ethyl acetate | ND | ||||
| trichloromethane | ND | ||||
| 1,1,1-trichloroethane | ND | ||||
| n-butanol | ND | ||||
| benzene | 0.2 | 0.4 | 0.4 | 0.5 | 0.9 |
| 2-methylhexane | ND | ||||
| 2,3-dimethylpentane | ND | ||||
| 3-methylhexane | ND | ||||
| heptane | 0.5 | 0.5 | |||
| trichloroethene | ND | ||||
| propyl acetate | ND | ||||
| methylcyclohexane | ND | ||||
| 4-methylpentan-2-one | ND | ||||
| toluene | 0.2 | 2.3 | 2.1 | 3.3 | 4.8 |
| octane | ND | ||||
| tetrachloroethene | ND | ||||
| butyl acetate | ND | ||||
| ethylbenzene | 0.3 | 0.4 | 0.3 | 0.5 | 0.7 |
| m+p-xylene | 0.3 | 1.4 | 1.2 | 2.0 | 2.7 |
| styrene | ND | ||||
| o-xylene | 0.3 | 0.5 | 0.4 | 0.6 | 0.8 |
| nonane | ND | ||||
| alpha pinene | ND | ||||
| propylbenzene | ND | ||||
| 1,3,5-trimethylbenzene | ND | ||||
| beta pinene | ND | ||||
| decane | ND | ||||
| 1,2,4-trimethylbenzene | 0.6 | 0.7 | 0.9 | ||
| limonene | ND | ||||
| undecane | ND | ||||
| dodecane | ND | ||||
| tetradecane | 0.6 | 0.7 | |||
ND = Not detected.
Figure 1: MfE benzene annual average 2007
Annual average benzene results at all sites were within both the current ambient air quality guideline of 10.0 (µg/m3) and the future guideline value of 3.6 (µg/m3) (effective 2010). No benzene result was above 2 µg/m3.
7.6 Particulate matter (PM10) 2007
PM10 is monitored at Greers Road, Burnside, Gavin Street, Penrose and Kowhai Intermediate, Kingsland sites, using Thermo FH62-C14 Beta Gauges. Twenty-four hour averages have been calculated from 10-minute averages recorded by the instruments. All PM10 concentrations are 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.
| Site |
Maximum 24-hour average (µg/m3) |
99.5 percentile 24-hour average (µg/m3) |
|---|---|---|
| Gavin Street, Penrose | 46.2 (28 May) |
41.1 |
| Kowhai Intermediate, Kingsland | 33.6 (29 May) |
32.5 |
| Greers Road, Burnside | 110.3 (6 August) |
68.9 |
There were no exceedances of the ambient air quality standard (50 µg/m3) in Auckland during the 12-month period.
At Greers Road, Burnside, there were 11 exceedances of the 24-hour standard. Each exceedance and the date are listed in table 8 below. PM10 for 2007 for each site are shown in figures 52 to 54 (Kowhai), 55 to 57 (Gavin Street), and 58 to 60 (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 10 exceedances occurred in cooler months between June and August 2007.
Table 8: Greers Road, Burnside PM10 exceedances of the daily NES 2007
| Date |
Burnside PM10 (µg/m3) |
|---|---|
| 04/6/2007 | 60 |
| 13/6/2007 | 69 |
| 18/6/2007 | 63 |
| 19/6/2007 | 56 |
| 08/7/2007 | 69 |
| 09/7/2007 | 51 |
| 23/7/2007 | 78 |
| 27/7/2007 | 61 |
| 28/7/2007 | 67 |
| 06/8/2007 | 110 |
Note: National Environmental Standard for PM10 = 50 µg/m³.
7.7 Total suspended particulates (TSP) 2007
TSP is measured as a seven-day average at, Gavin Street, Penrose, Kowhai Intermediate, Kingsland and Coles Place, St Albans. Maximum results and their dates (seven-day ending period) for each site are described below.
| Site | Maximum seven-day average (µg/m3) |
|---|---|
| Gavin Street, Penrose | 33 (28 February) |
| Kowhai Intermediate, Kingsland | 22 (30 May) |
| Coles Place, St Albans | 32 (26 July) |
There were no exceedances of the Ministry of Health (MoH) guideline of 60 µg/m3 at any site. The TSP concentrations in Auckland are shown in figures 2 and 3 while Christchurch TSP concentrations are shown in figures 4 and 5.
Figure 2: Auckland TSP seven-day average 2007
Gavin Street concentrations were generally between 8–35μg/m3 throughout the year, with the maximum value recorded in March. Kowhai values were slightly lower and had a peak level of around 23 μg/m3 in June.
Figure 3: Auckland TSP seven-day average 1994–2007
The Gavin Street site has shown a downward trend over this period. The Ministry of Health guideline was exceeded in June 1996 and June 1999. TSP results from the Mt Eden and Kowhai sites showed similar levels from 1994 to 2007. Kowhai had the highest TSP result in 2006.
Figure 4: Christchurch TSP seven-day average 2007
Values remained below the Ministry of Health guideline throughout the year. Peak seven-day TSP levels occurred from June to August.
Figure 5: Christchurch TSP seven-day average 2002–2007
Data from the Burnside site during this period showed the same seasonal variations each year, with peak levels occurring in June. The Ministry of Health guideline was exceeded in June 2003. Peak levels have shown a downward trend. The lowest winter TSP levels were recorded in 2007.
7.8 Lead (Pb) June–August 2007
Lead is measured from seven-day averaged TSP samples to derive a three-month average. The results are described in the table below. Figure 6 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.
| Site | June 2007 average (µg/m3) | July 2007 average (µg/m3) |
August 2007 average (µg/m3) |
Winter 2007 average (µg/m3) |
|---|---|---|---|---|
| Kowhai Intermediate, Kingsland | 0.020 | 0.010 |
0.006 |
0.012 |
| Gavin Street, Penrose | 0.020 | 0.010 |
0.006 |
0.012 |
| Coles Place, St Albans | 0.032 | 0.028 |
0.016 |
0.025 |
No site exceeded the three-month average guideline for lead (0.2 µg/m3).
Figure 6: MfE lead three-month average results 1996–2007
Lead results from all the monitoring sites were within the ambient air quality guideline of 0.2 µg/m3. The 3-month average levels in winter from 2003 to 2007 did not exceed 0.05 µg/m3.
Figure 7: MfE Burnside CO 1-hour fixed average January–December 2007
All carbon monoxide (CO) results at the Burnside monitoring site were within the 30 mg/m3 ambient air quality guideline. CO levels were low from January to April and October to December. The higher concentrations seen from May to September were less than one half of the guideline value.
Ambient air quality guideline for CO – 30 mg/m3
Figure 8: MfE Burnside CO 1-hour fixed average 2003–2007
All five years show the same trend (elevated levels during winter months). The peak level in 2006 was higher than those of previous years while the peak level for 2007 was the lowest.
Ambient air quality guideline for CO – 30 mg/m3
Figure 9: MfE Burnside CO 8-hour rolling average January–December 2007
All carbon monoxide (CO) 8-hour average results were below the national environmental standard for CO (10 mg/m3) in 2007. Slightly elevated CO levels were recorded from June to August.
National environmental standard for CO – 10 mg/m3
Figure 10: MfE Burnside CO 8-hour rolling average 2003–2007
The national environmental standard for carbon monoxide (CO) was only exceeded in 2006. Peak CO levels decreased in 2007 and were lower than peak levels from 2003 to 2006.
National environmental standard for CO – 10 mg/m3
Figure 11: MfE Burnside CO annual average 2003–2007
Carbon monoxide (CO) annual average results fluctuated but the 2007 result was lower than 2006. The lowest annual average CO was in 2005.
Figure 12: MfE Kowhai NO 1-hour fixed average January–December 2007
Monitoring at the Kowhai site ended in September. Nitrogen dioxide (NO2) levels at this site were all less than half the national environmental standard of 200 µg/m3. Levels appear slightly elevated during the winter months.
National environmental standard for NO2 – 200 µg/m3
Figure 13: MfE Kowhai NO2 1-hour fixed average 2004–2007
Monitoring at the Kowhai site ended in September 2007. NO2 levels at this site were all less than half the national environmental standard of 200 (µg/m3) from 2004 to 2007. Each year shows a winter time increase in NO2 levels.
National environmental standard for NO2 – 200 µg/m3
Figure 14: MfE Kowhai NO2 24-hour fixed average January–December 2007
NO2 levels were below the guideline value of 100 µg/m3. Levels are slightly elevated from May to August.
Ambient air quality guideline for NO2 – 100 µg/m3
Figure 15: MfE Kowhai NO2 24-hour fixed average 2004–2007
NO2 levels at Kowhai were all below the ambient air quality guideline throughout this period. No result was more than 50 µg/m3.
Ambient air quality guideline – 100 µg/m3.
Figure 16: MfE Kowhai NO2 annual average 2004–2007
NO2 levels at Kowhai from 2004 to 2007 remained fairly constant. There was a slight increase in annual average NO2 in 2007.
Figure 17: MfE Kowhai NO2 and NO 1-hour fixed average January–December 2007
NO levels appear to display a greater degree of variation compared to NO2. Peak NO levels occurred in May and June.
Monitoring at the Kowhai site ended in September 2007.
Figure 18: MfE Kowhai NO2 and NO 24-hour fixed average January–December 2007
This figure shows the same trend as that of figure 17. The peak daily NO level was recorded in June.
Figure 19: MfE Kowhai NO 1-hour fixed average 2004–2007
Hourly NO levels in 2007 were lower than previous years. The peak hourly NO in 2007 was less than 600 (µg/m3) while peak levels in previous years were all above 800 µg/m3. This trend is also reflected in the daily and annual average NO results from 2004 to 2007.
Figure 20: MfE Kowhai NO 24-hour fixed average 2004–2007
Hourly NO levels in 2007 were lower than previous years. The peak hourly NO in 2007 was less than 600 (µg/m3) while peak levels in previous years were all above 800 mg/m3. This trend is also reflected in the daily and annual average NO results from 2004 to 2007.
Figure 21: MfE Kowhai NO annual average 2004–2007
Hourly NO levels in 2007 were lower than previous years. The peak hourly NO in 2007 was less than 600 (µg/m3) while peak levels in previous years were all above 800 µg/m3. This trend is also reflected in the daily and annual average NO results from 2004 to 2007.
Figure 22: MfE Gavin Street NO2 1-hour fixed average January–December 2007
The national environmental standard for nitrogen dioxide (200 µg/m3) was not exceeded at the Gavin Street site in 2007.
Figure 23: MfE Gavin Street NO2 1-hour fixed average 1997–2007
The national environmental standard for nitrogen dioxide was only exceeded once (2005) in twelve years (1997 to 2007).
Validation of results in 2008 showed that NO2 exceedences in 2001 were due to instrument error. These results have been considered invalid and removed from the data set.
National environmental standard for NO2 – 200 µg/m3
Figure 24: MfE Gavin Street NO2 24-hour fixed average January–December 2007
All nitrogen dioxide daily results at the Gavin Street site were within the ambient air quality guideline of 100 µg/m3. Daily results were slightly elevated during the winter months but these peaks were all below 60 µg/m3.
Ambient air quality guideline for NO2 – 100 µg/m3
Figure 25: MfE Gavin Street NO2 24-hour fixed average 1 January 1997–2007
Nitrogen dioxide daily averages showed very similar yearly trends from 1997 to 2007 with peaks occurring in June.
Validation of results in 2008 showed that NO2 exceedences in 2001 were due to instrument error. These results have been considered invalid and removed from the data set. As a result, no daily NO2 result was above the ambient air quality guideline of 100 µg/m3.
Ambient air quality guideline for NO2 – 100 µg/m3
Figure 26: MfE Gavin Street NO2 annual average 1997–2007
There was little change in annual nitrogen dioxide levels from 1997 to 2007. The highest annual average was in 2001 while the lowest was in 1998. The annual average NO2 in 2007 was slightly lower than the 2006 level.
Figure 27: MfE Gavin Street NO2 and NO 1-hour fixed average January–December 2007
NO levels appear to display a greater degree of variation throughout the year compared to NO2levels. Peak NO levels occurred in May and June.
Figure 28: MfE Gavin Street NO2 and NO 24-hour fixed average January–December 2007
The range of NO results reflects the same trend as that of figure 27. NO levels during most of the year were generally below 100 (µg/m3) except for peaks from April to July.
Figure 29: MfE Gavin Street NO 1-hour fixed average 1997–2007
Hourly NO levels at Gavin Street decreased in 2007 than previous years. The peak hourly NO in 2007 was less than 700 µg/m3. The highest hourly NO was over 1000 (µg/m3) in 1997. This trend is also reflected in the daily and annual average NO results from 1997 to 2007. The lowest annual average was recorded in 2007.
Figure 30: MfE Gavin Street NO 24-hour fixed average 1997–2007
Hourly NO levels at Gavin Street decreased in 2007 than previous years. The peak hourly NO in 2007 was less than 700 µg/m3. The highest hourly NO was over 1000 (µg/m3) in 1997. This trend is also reflected in the daily and annual average NO results from 1997 to 2007. The lowest annual average was recorded in 2007.
Figure 31: MfE Gavin Street NO annual average 1997–2007
Hourly NO levels at Gavin Street decreased in 2007 than previous years. The peak hourly NO in 2007 was less than 700 µg/m3. The highest hourly NO was over 1000 (µg/m3) in 1997. This trend is also reflected in the daily and annual average NO results from 1997 to 2007. The lowest annual average was recorded in 2007.
Figure 32: MfE Burnside NO2 1-hour fixed average January–December 2007
All hourly NO2 results in Burnside were below the national environmental standard of 200 mg/m3. No result was above 70 (µg/m3) at this monitoring site.
National environmental standard for NO2 – 200 µg/m3
Figure 33: MfE Burnside NO2 1-hour fixed average 2003–2007
No exceedence of the national environmental standard occurred from 2003 to 2007 at the Burnside site. All hourly NO2 results were less than half of the standard.
The national environmental standard for NO2 is 200 µg/m3.
National environmental standard for NO2 – 200 µg/m3
Figure 34: MfE Burnside NO2 24-hour fixed average January–December 2007
The daily NO2 results for 2007 were all within the ambient air quality guideline of 100 (µg/m3) at the Burnside site. NO2 levels were slightly higher from June to August. All results were below 40 µg/m3, which is less than half the guideline value.
Ambient air quality guideline for NO2 – 100 µg/m3
Figure 35: MfE Burnside NO2 24-hour fixed average 2003–2007
Daily NO2 levels in the past five years were all below the ambient air quality guideline of 100 µg/m3. The highest daily NO2 average in Burnside occurred in the winter of 2005. Results from 2007 show a similar yearly trend of elevated levels during winter.
Figure 36: MfE Burnside NO2 annual average 2003–2007
NO2 annual levels at Burnside were very similar in the past five years. All annual average NO2 results were below 15 µg/m3 from 2003 to 2007.
Figure 37: MfE Burnside NO2 and NO 1-hour fixed average January–December 2007
The hourly NO levels in Burnside peak in August and are lowest during the months of November and December. Hourly NO2 levels have less variation during the year than hourly NO levels.
Figure 38: MfE Burnside NO2 and NO 24-hour fixed average January–December 2007
The daily NO averages in Burnside have a greater degree of variation during the year, reflecting the hourly trend in figure 37. Both NO and NO2 results peaked in August.
Figure 39: MfE Burnside NO 1-hour fixed average 2003–2007
Yearly NO (1-hour average) variations in Burnside were similar from 2003 to 2007 with the highest result obtained in 2006. The second highest hourly average NO was recorded in 2007. This trend is also reflected in the daily and annual averages which show a peak in 2006. Annual average NO in 2007 was slightly higher than the 2003 average.
Figure 40: MfE Burnside NO 24-hour fixed average 2003–2007
Yearly NO (1-hour average) variations in Burnside were similar from 2003 to 2007 with the highest result obtained in 2006. The second highest hourly average NO was recorded in 2007. This trend is also reflected in the daily and annual averages which show a peak in 2006. Annual average NO in 2007 was slightly higher than the 2003 average.
Figure 41: MfE Burnside NO annual average 2003–2007
Yearly NO (1-hour average) variations in Burnside were similar from 2003 to 2007 with the highest result obtained in 2006. The second highest hourly average NO was recorded in 2007. This trend is also reflected in the daily and annual averages which show a peak in 2006. Annual average NO in 2007 was slightly higher than the 2003 average.
Figure 42: MfE Gavin Street SO2 1-hour fixed average January–December 2007
There was no exceedence of the national environmental standards for SO2 in 2007. Hourly SO2 levels at Gavin Street were all below 50 µg/m3. The national environmental standard for SO2 is 350 µg/m3.
National environmental standard for SO2 – 350 µg/m3
Figure 43: MfE Gavin Street SO2 1-hour fixed average 2003–2007
The hourly SO2 levels at Gavin Street for the past five years have been within the same range. Peaks occurred in 2005 but these were below 60 µg/m3. The national environmental standard of 350 µg/m3 for SO2 has not been exceeded from 2003 to 2007.
National environmental standard for SO2 – 350 µg/m3
Figure 44: MfE Gavin Street SO2 24-hour fixed average January–December 2007
All daily SO2 results at Gavin Street were below the ambient air quality guideline of 120 µg/m3. Daily SO2 results in June and July were slightly higher than other months. Results from August to December were very low (less than 10 µg/m3).
This trend is also reflected in the Gavin Street daily and annual SO2 results from 2003 to 2007. The lowest annual average SO2 was recorded in 2007 while the highest was in 2005 (6.5 µg/m3).
Ambient air quality guideline for SO2 – 120 µg/m3
Figure 45: MfE Gavin Street SO2 24-hour fixed average 2003–2007
All daily SO2 results at Gavin Street were below the ambient air quality guideline of 120 µg/m3. Daily SO2 results in June and July were slightly higher than other months. Results from August to December were very low (less than 10 µg/m3).
This trend is also reflected in the Gavin Street daily and annual SO2 results from 2003 to 2007. The lowest annual average SO2 was recorded in 2007 while the highest was in 2005 (6.5 µg/m3).
Ambient air quality guideline for SO2 – 120 µg/m3
Figure 46: MfE Gavin Street SO2 annual average 2003–2007
All daily SO2 results at Gavin Street were below the ambient air quality guideline of 120 µg/m3. Daily SO2 results in June and July were slightly higher than other months. Results from August to December were very low (less than 10 µg/m3).
This trend is also reflected in the Gavin Street daily and annual SO2 results from 2003 to 2007. The lowest annual average SO2 was recorded in 2007 while the highest was in 2005 (6.5 µg/m3).
Figure 47: MfE Burnside SO2 1-hour fixed average January–December 2007
All hourly SO2 results at Burnside were within the national environmental standard of 350 µg/m3 in 2007. All results were less than 55 µg/m3. This trend is also reflected in hourly SO2 levels for the previous years. There was one result in 2003 that was over 100 µg/m3 but all other results from 2003 to 2007 were below 55 µg/m3.
National environmental standard for SO2 – 350 µg/m3
Figure 48: MfE Burnside SO2 1-hour fixed average 2003–2007
All hourly SO2 results at Burnside were within the national environmental standard of 350 µg/m3 in 2007. All results were less than 55 µg/m3. This trend is also reflected in hourly SO2 levels for the previous years. There was one result in 2003 that was over 100 µg/m3 but all other results from 2003 to 2007 were below 55 µg/m3.
National environmental standard for SO2 – 350 µg/m3
Figure 49: MfE Burnside SO2 24-hour fixed average January–December 2007
No daily SO2 average at Burnside was above the ambient air quality guideline of 120 µg/m3. All results were below 15 µg/m3. There was a similar trend in daily SO2 levels for the past five years. Most of the daily SO2 results were below 20 µg/m3 with peaks occurring in 2003 and 2006. The lowest annual average was recorded in 2007.
Ambient air quality guideline for SO2 – 120 µg/m3
Figure 50: MfE Burnside SO2 24-hour fixed average 2003–2007
No daily SO2 average at Burnside was above the ambient air quality guideline of 120 µg/m3. All results were below 15 µg/m3. There was a similar trend in daily SO2 levels for the past five years. Most of the daily SO2 results were below 20 µg/m3 with peaks occurring in 2003 and 2006. The lowest annual average was recorded in 2007.
Ambient air quality guideline for SO2 – 120 µg/m3
Figure 51: MfE Burnside SO2 annual average 2003–2007
No daily SO2 average at Burnside was above the ambient air quality guideline of 120 µg/m3. All results were below 15 µg/m3. There was a similar trend in daily SO2 levels for the past five years. Most of the daily SO2 results were below 20 µg/m3 with peaks occurring in 2003 and 2006. The lowest annual average was recorded in 2007.
Figure 52: MfE Kowhai PM10 24-hour fixed average January–December 2007
All daily PM10 levels at the Kowhai site were below the national environmental standard of 50 µg/m3. Monitoring at this site was from January to September 2007. The highest result was recorded in June.
National environmental standard for PM10 – 50 µg/m3
Figure 53: MfE Kowhai PM10 24-hour fixed average 2004–2007
The national environmental standard was not exceeded at the Kowhai site from 2004 to 2007. The highest daily PM10 result was in 2005. Winter PM10 levels in 2007 were lower than previous years.
Figure 54: MfE Kowhai PM10 annual average 2004–2007
There is a decreasing trend in annual average PM10 levels at the Kowhai site from 2004 to 2007. All annual PM10 levels were below the ambient air quality guideline value of 20 µg/m3.
Ambient air quality guideline for PM10 – 20 µg/m3
Figure 55: MfE Gavin Street PM10 24-hour fixed average January–December 2007
All daily PM10 levels were below the national environmental standard of 50 µg/m3. Elevated daily PM10 levels occurred in June, July, and September. Daily PM10 levels for the rest of the year were below 35 µg/m3.
National environmental standard for PM10 – 50 µg/m3
Figure 56: MfE Gavin Street PM10 24-hour fixed average 2003–2007
All daily PM10 results from 2003 to 2007 were below the national environmental standard of 50 µg/m3. The past five years had elevated PM10 levels during the winter months.
National environmental standard for PM10 – 50 µg/m3
Figure 57: MfE Gavin Street PM10 annual average 2003–2007
All annual average PM10 levels from 2003 to 2007 were below the ambient air quality guideline of 20 µg/m3. The lowest annual average at Gavin Street was recorded in 2005 while the highest was in 2003. Annual average PM10 remained the same in 2006 and 2007.
Figure 58: MfE Burnside PM10 24-hour fixed average January–December 2007
There were 11 exceedences of the national environmental standard for daily PM10 at the Burnside site in 2007. These occurred from May to August. The highest exceedence was 110 µg/m3 (August).
National environmental standard for PM10 – 50 µg/m3.
Figure 59: MfE Burnside PM10 24-hour fixed average 2003–2007
There have been yearly exceedences of the national environmental standard for PM10 at the Burnside site from 2003 to 2007. The highest daily value was recorded in 2006. Daily PM10 results in 2006 and 2007 had peak levels more than double the PM10 standard of 50 µg/m3.
Figure 60: MfE Burnside PM10 annual average 2003–2007
Annual average PM10 in 2003 and 2004 were above the ambient air quality guideline of 20 µg/m3. Results for 2005 to 2007 were all below the guideline value with 2007 recording the lowest annual average PM10.
Ambient air quality guideline for PM10 – 20 µg/m3
7.9 Analysis of exceedances
7.9.1 Exceedances at Greers Road, Burnside
The only exceedances recorded during 2007 were at Greers Road, Burnside, and for PM10 daily averages. All parameters at the other two Auckland sites were below the national environmental standards (NES) for air quality.
Time of year
The PM10 daily average NES of 50 µg/m3 was exceeded on 11 days during 2007, during the cooler months from late May to early August. On three occasions the exceedances occurred on consecutive days (18–19 June, 8–9 July and 27–28 July).
Time of week
It is interesting to note that five of the 11 exceedances occurred on a Monday, with all other week days having one exceedance each (except Thursday). This is probably coincidental, as there is no apparent reason (other than response to weather) why wood burning should be higher on Mondays.
Time of day
The typical diurnal trend in PM10 during winter is shown in figure 61. Here PM10 hourly averages for those days where the daily PM10 average exceeded 50 µg/m3 are plotted against time of day. From figure 61, the biggest contributions to PM10 were between the hours of 18:00 and 05:00. This would suggest contributions from wood burning for home heating.
Temperature
Figures 62, 63 and 64 plot PM10 hourly averages for those days where the daily PM10 average exceeded 50 µg/m3 against hourly average temperature measured at 1.5 m, hourly average temperature measured at 10 m, and the difference between the hourly averages of the two temperature heights. From figure 62, the biggest contributions to PM10 were when temperature measured at 1.5 m was below 10°C. From figure 63, the biggest contributions to PM10 were when temperature measured at 10 m was below 12°C. From figure 64, the biggest contributions to PM10 were when temperature difference between 10 m and 1.5 m was greater than zero, ie, when temperature inversion conditions prevailed. This is consistent with the trapping of pollutants and subsequent higher concentrations expected during temperature inversion conditions.
Wind direction
Figure 65 plots PM10 hourly averages for those days where the daily PM10 average exceeded 50 µg/m3 against hourly average wind directions. From figure 65, no wind direction seems to contribute significantly higher concentrations than others. This is consistent with an area wide diffuse (as opposed to point/line) source of pollution. There were very few data points in the sector 120 degrees to 180 degrees as wind frequency from this sector is usually low.
Wind speed
Figure 66 plots PM10 hourly averages for those days where the daily PM10 average exceeded 50 µg/m3 against hourly average wind speeds. From figure 66, the biggest contributions to PM10 were when wind speed was below 1.5 m/s, ie, low wind speed conditions. This is consistent with reduced dispersion under low wind speed conditions.
NO
Figure 67 plots PM10 hourly averages for those days where the daily PM10 average exceeded 50 µg/m3 against hourly average NO. From figure 67, a positive linear relationship seems to exist between PM10 and NO concentrations. This is expected as PM10 and NO is co-generated during wood burning.
CO
Figure 68 plots PM10 hourly averages for those days where the daily PM10 average exceeded 50 µg/m3 against hourly average CO. From figure 68, a positive linear relationship seems to exist between PM10 and CO concentrations. This is expected as PM10 and CO is co-generated during wood burning.
SO2
Figure 69 plots PM10 hourly averages for those days where the daily PM10 average exceeded 50 µg/m3 against hourly average SO2. From figure 69, no relationship seems to exist between PM10 and SO2 concentrations. This is expected as wood burning does not generate SO2.
Conclusions
From the univariate comparisons of meteorological parameters and other pollutants as discussed above, it can be concluded that the PM10 exceedances were most likely due to wood burning for home heating during the colder months, especially in the evenings, exacerbated by temperature inversions trapping the pollutants and low wind speed conditions preventing effective dispersion of pollutants.
Figure 61: MfE Burnside PM10 vs time of day
The biggest contributions to PM10 during days when exceedences occurred in 2007 were between the hours of 18:00 and 05:00.
Figure 62: MfE Burnside PM10 vs 1.5 m temperature
The biggest contributions to PM10 during days when exceedences occurred in 2007 were when temperature measured at 1.5 m was below 10°C.
Figure 63: MfE Burnside PM10 vs 10 m temperature
The biggest contributions to PM10 during days when exceedences occurred were when temperature measured at 10 m was below 12ºC.
Figure 64: MfE Burnside PM10 vs temperature diff 10 m–1.5 m
The biggest contributions to PM10 during days when exceedences occurred were when the temperature difference between 10 and 1.5 metres was greater than zero. This is when temperature inversions occur.
Figure 65: MfE Burnside PM10 vs wind direction
No wind direction seemed to contribute significantly higher PM10 levels than others. There were very few data points from 120 to 180 degrees as wind frequency from this sector is usually low.
Figure 66: MfE Burnside PM10 vs wind speed
The figure shows that contributions to PM10 when exceedences occurred began when wind speed was below 1.5 m/s and peaked at a wind speed of 0.5 m/s.
Figure 67: MfE Burnside PM10 vs NO
A positive linear relationship seems to exist between PM10 and NO levels. This relationship is more defined at PM10 levels below 60 µg/m3and NO levels below 80 µg/m3.
Figure 68: MfE Burnside PM10 vs CO
A positive linear relationship seems to exist between PM10 and CO levels. This relationship is more defined at PM10 levels below 150 µg/m3 and CO levels below 3.5 mg/m3.
Figure 69: MfE Burnside PM10 vs SO2
The figure shows that no relationship seems to exist between PM10 and SO2 concentrations.
