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9 Summary

Air quality monitoring of CO, NO2 and SO2 has been carried out in a number of urban centres within New Zealand. For the majority of the time, concentrations of these contaminants are 'excellent' or 'good' in most locations. Of these contaminants, the main concerns arise from CO and NO2 concentrations at sites located to major roadways such as Khyber Pass Road and in areas such as Christchurch, where elevated concentrations at 'residential' sites can occur.

Air quality monitoring for O3 has been carried out at a number of locations within Auckland and at two sites on the outskirts of Christchurch. Although guidelines have not been exceeded at these sites, a large proportion of the data were within the 'acceptable' category and in Auckland up to 15% of the data were in the 'alert' air quality category.

Concentrations of benzene have been monitored in Auckland, Christchurch, Hamilton, Dunedin, Nelson, in the Bay of Plenty and on the West Coast. Annual average concentrations have been within the current guideline of 10 µgm-3 (annual average) and 2010 guideline (3.6 µgm-3) at most 'residential' sites. Guideline exceedences have been recorded at Khyber Pass Road in Auckland and at Riccarton Road in Christchurch.

Measurements of BaP were carried out in Christchurch during 1999. Data show strong correlations with PM10 concentrations and indicate that the annual average BaP concentrations are at least 4 ngm-3, more than 10 times the guideline concentration. Based on these results, it is likely that BaP concentrations also exceed ambient air quality guidelines in areas where elevated PM10 concentrations occur as a result of solid fuel burning for domestic home heating. Concentrations of PM10 in New Zealand, documented in the MfE report Monitoring of PM10 in New Zealand (MfE, 2003) show PM10 concentrations of concern in many locations where solid fuel burning is a major contributor. Consequently, it is likely that concentrations of BaP are of concern in many urban areas of New Zealand.

Table 9.1: Areas where CO, NO2, SO2 and O3 have exceeded guideline values between 1992 and 2002

CO NO2 SO2 O3 Benzene BaP
  • Auckland - 'traffic' sites
  • Christchurch 'traffic' and 'residential' sites
  • Wellington 'traffic' sites
  • Dunedin 'residential' sites
  • Auckland 'traffic' sites

None

None
  • Auckland 'traffic' sites
  • Christchurch 'traffic' sites
  • Christchurch 'residential' sites
  • Also likely in other urban areas of New Zealand
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