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 and some New Zealand guidelines are described in table 1 below.
The criteria used for TSP, 60 μg/m3 (seven-day average), was previously used by the Ministry of Health. This has been superseded by the ambient air quality guidelines but is still useful for analysing the results of the monitoring data.
Table 1: National environmental standards and guidelines6
| Air pollutant | National environmental standards 2004 | Ministry for the Environment Ambient Air Quality Guidelines 2002 and other | Averaging period | National environmental standards permissible excess |
|---|---|---|---|---|
| Carbon monoxide | 10 mg/m3 | 10 mg/m3 30 mg/m3 | 8-hour average 1-hour average | One 8-hour period in a 12‑month period |
| Nitrogen dioxide | 200 µg/m3 | 100 µg/m3 200 µg/m3 | 24-hour average 1-hour average | 9 hours in a 12-month period |
| Sulfur dioxide | 350 µg/m3 570 µg/m3 | 120 µg/m3 350 µg/m3 | 24-hour average 1-hour average 1-hour average | 9 hours in a 12-month period Not to be exceeded at any time |
| Benzene– Year 2002– Year 2010 | 10 µg/m3 3.6 µg/m3 | Annual average Annual average | ||
| 1,3-Butadiene | 2.4 µg/m3 | Annual average | ||
| Fine particulate (PM10) | 50 µg/m3 | 20 µg/m3 50 µg/m3 | Annual average 24-hour average | One 24-hour period in a 12‑month period |
| Total suspended particulate (TSP) | 60 µg/m3 (Ministry of Health) | 7-day average | ||
| Lead | 0.2 µg/m3 | 3-month average |
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4 Ambient Air Quality Guidelines and Standards
July 2009
© Ministry for the Environment