4 Ambient Air Quality Guidelines and Standards
In October 2004, the Ministry for the Environment introduced the National Environmental Standards (NES) for Air Quality. The NES includes five standards for ambient (outdoor) air quality. Four of these standards and some New Zealand guidelines are described in table 1 below. The fifth standard is not included as it relates to ozone, which is not measured at the sites discussed in this report.
The criteria used for total suspended particulate (TSP), 60 µg/m3 (seven-day average), was previously used by the Ministry of Health (MoH). This has been superseded by the ambient air quality guidelines but is still useful for analysing the results of the monitoring data.
Air pollutant |
Averaging period |
National Environmental Standards 2004 |
Ministry for the Environment Ambient Air Quality Guidelines 2002 and other |
National Environmental Standards permissible excess |
|---|---|---|---|---|
Carbon monoxide |
8-hour average |
10 mg/m3 |
10 mg/m3 |
One 8-hour period in a 12-month period |
1-hour average |
|
30 mg/m3 |
|
|
Nitrogen dioxide |
24-hour average |
|
100 µg/m3 |
|
1-hour average |
200 µg/m3 |
200 µg/m3 |
9 hours in a 12-month period |
|
Sulphur dioxide |
24-hour average |
|
120 µg/m3 |
|
1-hour average |
350 µg/m3 |
350 µg/m3 |
9 hours in a 12-month period |
|
1-hour average |
570 µg/m3 |
|
Not to be exceeded at any time |
|
Benzene |
|
|
|
|
– Year 2002 |
Annual average |
|
10 µg/m3 |
|
– Year 2010 |
Annual average |
|
3.6 µg/m3 |
|
1,3-Butadiene |
Annual average |
|
2.4 µg/m3 |
|
Fine particulate (PM10) |
Annual average |
|
20 µg/m3 |
|
24-hour average |
50 µg/m3 |
50 µg/m3 |
One 24-hour period in a 12‑month period |
|
Total suspended particulate (TSP) |
7-day average |
|
60 µg/m3 (MoH) |
|
Lead |
3-month average |
|
0.2 µg/m3 |
|
