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6.3 Regional Ambient Air Quality Guidelines

Table 6-5 Regional Ambient Air Quality Guidelines (RAAQG)

Contaminant Averaging Time Waikato Region Levels
Carbon monoxide (CO) 1 hour 30 mg/m3
  8 hours 10 mg/m3
Nitrogren dioxide (NO2) 1 hour 200 µg/m3
  24 hours 100 µg/m3
  Annual 30 µg/m3
Particulate matter (PM10) 24 hours 50 µg/m3
  Annual 20 µg/m3
Sulphur dioxide (SO2) 1 hour 350 µg/m3
  24 hour 120 µg/m3
Agricultural Crops Annual and Winter average 30 µg/m3
Forest and natural vegetation Annual and winter average 20 µg/m3
Lichen Annual 10 µg/m3
Ozone (O3) 1 hour 150 µg/m3
  8 hours 100 µg/m3
Forests 6 months 21,400 µg/m3 – h
Semi-natural vegetation 3 months 6,420 µg/m3 – h
Crops (yield) 3 months 6,420 µg/m3 – h
Crops (visible injury) mean daytime vpd below 1.5kPa 5 days 428 µg/m3 – h
Crops (visible injury) mean daytime vpd above 1.5kPa 5 days 1,070 µg/m3 – h
Hydrogen sulphide (H2S) 1 hour 7 µg/m3
Lead content of PM10 3 month moving average 0.2 µg/m3
Benzene (current) Annual 10 µg/m3
Benzene (2010) Annual 3.6 µg/m3


  • The RAAQG have been adopted as maximum acceptable levels of priority contaminants for managing ambient air quality in the Waikato Region. The RAAQG are not standards. The acceptable level of these contaminants in air in any given situation will depend upon a site specific analysis in accordance with the policies in Section 6.1.3.
  • The application and interpretation of the guideline values shall be in accordance with Chapter 3 of the Ambient Air Quality Guidelines, Ministry for the Environment, May 2002.
  • In the absence of a regional guideline value regard shall be had to relevant national and/or international criteria as appropriate.
  • The specific monitoring methods to be used will, as a matter of preference, be those specified in the most recent version of the Ministry for the Environment’s Ambient Air Quality Guidelines. Where those guidelines are not specific, or are out of date, the monitoring method to be used will be determined on a case by case basis having regard to best practice.
  • In some circumstances, such as discharges from the mineral processing industry, PM10 may not be the appropriate indicator of air quality effects from particulate matter. In those circumstances measures such as total suspended particulate and/or dust deposition may be more appropriate.
  • These Guidelines are not to be used as ‘pollute up to’ levels in the Region.
  • The levels in the Guidelines are concerned with the cumulative impacts of discharges into air from human activities and natural processes.
  • When using the Guidelines to calculate allowable emission standards for single sources consideration should be given to the proportion of the available air quality increment that should be allocated to that single source. Consideration also needs to be given to background levels of contaminants so that the Guideline values are not exceeded.
  • Critical levels for nitrogen dioxide assume that either O3 or SO2 are also present at near guideline levels. Critical levels for ozone are expressed as a cumulative exposure over a concentration threshold referred to as AOT40 values (accumulative exposure over a threshold of 85.6 µg/m3, at O°C), calculated as the sum of the difference between hourly ambient ozone concentrations and 85.6 µg/m3, when ozone concentrations exceed 85.6 µg/m3. Ozone is only measured during daylight hours with a clear global radiation of 50Wm-2 or greater; vpd = vapour pressure deficit.
  • The hydrogen sulphide value is based on odour nuisance and may be unsuitable for use in geothermal areas.

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