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Key findings - Carbon monoxide

Current situation

In 2008, all sites in New Zealand monitoring carbon monoxide met the 8-hour national standard and the 1-hour national guideline.

The Auckland (Khyber Pass Road), Rotorua and Wellington monitoring sites, the results of which are shown in figures 1, 2 and 3, are located close to major roads. This type of location is the most likely to be affected by elevated levels of carbon monoxide. The Auckland (Takapuna) and both Christchurch monitoring sites are located in residential areas.

In a similar finding, shorter monitoring surveys conducted at peak traffic locations in the Hawke’s Bay region in 2008 reported that carbon monoxide levels at these locations were well below the 8-hour standard and 1-hour national guideline.8

Figure 3 shows the annual averages for Auckland (Khyber Pass Road) are much higher than the other sites. This is due largely to the relatively constant carbon monoxide pollution from vehicles that occurs at this site.

Figure 1: Maximum carbon monoxide levels, 8-hour average, 1988–2008

Figure 1: Maximum carbon monoxide levels, 8-hour average, 1988–2008

Source: Auckland Regional Council,9 Environment Canterbury,10 Environment Bay of Plenty,11 Greater Wellington.12

Year Auckland (Khyber Pass Road) (mg/m3) Auckland (Takapuna) (mg/m3) Rotorua
(mg/m3)
Wellington
(mg/m3)
Christchurch (St Albans)
(mg/m3)
Christchurch (Burnside)
(mg/m3)
1988         15  
1989         23  
1990         29  
1991         23  
1992         29  
1993         22  
1994         28  
1995   6.9     14  
1996   8.7     20  
1997 14.3 9.6     19  
1998 14.2 7.3     13  
1999 11.4 8.7     18  
2000 9.8  -     13  
2001 9.3 8.6     12  
2002 8.7 6.6     14  
2003 8.6 6.7     10 9
2004 8.6 5.9   4.7 10 6.2
2005 7.4 6.3 3.8 3.2 8 8.1
2006 7.2 6.3 2.6 3.7 11 10.3
2007 6.6 5.7 1.5 3.6 6 5.5
2008 6.1 4.7   3.1 8 6.1

Figure 2: Maximum carbon monoxide levels, 1-hour average, 1988–2008

Figure 2: Maximum carbon monoxide levels, 1-hour average, 1988–2008

Source: Auckland Regional Council,9 Environment Canterbury,10 Environment Bay of Plenty,11 Greater Wellington.12

Year Auckland (Khyber Pass Road) (mg/m3) Auckland (Takapuna) (mg/m3) Rotorua
(mg/m3)
Wellington
(mg/m3)
Christchurch (St Albans)
(mg/m3)
Christchurch (Burnside)
(mg/m3)
1988         26  
1989         31  
1990         36  
1991         31  
1992         34  
1993         38  
1994         41  
1995   15.8     25  
1996 14.1 16.5     27  
1997 21.8 17.2     27  
1998 18.7 14.0     20  
1999 18.2 13.7     21  
2000 17.7  -     18  
2001 14.9 6.2     16  
2002 14.5 11.6     15  
2003 12.4 11.0     14 11
2004 13.3 7.5   7.7 12 8.4
2005 10.1 8.7 6.0 6.7 10 10.5
2006 10.6 8.0 5.1 6.0 14 14.4
2007 9.7 6.8 1.6 6.1 8 9.2
2008 8.7 7.4   5.1 10 8.7

Figure 3: Annual carbon monoxide levels, 1989–2008

Source: Auckland Regional Council,9 Environment Canterbury,10 Environment Bay of Plenty,11 Greater Wellington.12

Year Auckland (Khyber Pass Road) (mg/m3) Auckland (Takapuna) (mg/m3) Rotorua
(mg/m3)
Wellington (Central)
(mg/m3)
Christchurch (St Albans)
(mg/m3)
Christchurch (Burnside)
(mg/m3)
1989         0.9  
1990         1.2  
1991          -  
1992         1.8  
1993         1.4  
1994         0.9  
1995         1  
1996         1  
1997 3.4 0.8     0.9  
1998 2.9 0.8     0.8  
1999 2.7  -     0.8  
2000 2.5  -     0.6  
2001 2  -     0.7  
2002 2 0.7     0.6  
2003 2 0.8     0.6 0.6
2004 2.2 0.5   0.8 0.5 0.5
2005 1.8 0.5 0.6 0.6 0.4 0.5
2006 1.6 0.7 0.4 0.6 0.5 0.6
2007 1.4 0.5  - 0.5 0.3 0.6
2008 1.2 0.4   0.6 0.3 0.5

Trend

Recent trend

Carbon monoxide was reported on in Environment New Zealand 2007. Since then, there has been a general decrease (improvement) in the 1-hour and 8-hour maximums, and the annual averages at most sites (see the new data presented in figures 1–3).

There have been no detected exceedances of the carbon monoxide 8-hour national standard at any monitoring site in New Zealand since 2006, when six exceedances and four breaches occurred. Five of the exceedances and all of the four breaches occurred at the St Albans’s site in Christchurch during winter. The other exceedance occurred at the Burnside site in Christchurch, also during winter.

Long-term trend

The trends for long-term monitoring sites – Auckland (Khyber Pass Road and Takapuna) and Christchurch (St Albans) – also show a general decreasing (improving) trend in ambient carbon monoxide levels. This is largely due to improvements in New Zealand’s vehicle fleet. In 1998, the removal of import tariffs made it cheaper to import vehicles from other countries.1 Until recently, a used imported vehicle had better exhaust emissions control technology than the same vehicle purchased new in New Zealand. This was due to the imported vehicle being manufactured to more rigorous vehicle emissions standards in the country of origin.13 In the late 1990s, a voluntary agreement resulted in many New Zealand new vehicles being fitted with emissions control technology.14 Advancements in vehicle technology, the introduction and amendments of the Vehicle Exhaust Emissions Rule, and fuel quality requirements have also helped.