Other air pollutants

This section provides data on three air pollutants at monitoring stations in New Zealand

  • nitrogen dioxide (NO₂)
  • sulphur dioxide (SO₂)
  • carbon monoxide (CO)

These air pollutants can cause a range of health effects, including respiratory problems. Air quality standards and guidelines have been developed to provide some level of protection against health risks.

Most sites met the nitrogen dioxide guidelines

Monitoring nitrogen dioxide is important, as it is associated with respiratory illnesses. Children, asthmatics, and people with chronic lung disease are most at risk [3].

Between 2004 and 2016, five out of 13 monitoring stations exceeded the national one-hour average standard (Figure 1). All five monitoring stations had a traffic- and/or industrial-focus:

  • Te Rapa Road (Hamilton)
  • Khyber Pass (Auckland)
  • Queen Street (Auckland)
  • Port of Auckland (Auckland)
  • Penrose (Auckland)

Figure 1: Number of exceedances of the NESAQ’s threshold (one-hour average), 2004-2016

Only one monitoring station exceeded the WHO annual average guideline between 2004 and 2016. The monitoring station Queen Street in Auckland, a traffic-focussed station, exceeded the guideline in nine out of 12 monitored years. Queen Street is a high-traffic, inner city monitoring station surrounded by tall buildings enabling the accumulation of motor vehicle emissions [2].

For more information about nitrogen dioxide, please download the factsheet.

Six out of nine monitoring sites exceeded the daily WHO guideline for SO₂ between 2008 and 2017

Monitoring sulphur dioxide is important, as it is associated with respiratory illnesses such as bronchitis. People with asthma or other chronic lung problems are particularly at risk [3].

Four (out of nine) monitoring sites exceeded the lower 350µg/m3 threshold of the national one-hour average standard between 2008 and 2017 (Figure 2):

  • Woolston (Christchurch)
  • Port of Auckland (Auckland)
  • Totara St (Mount Maunganui)
  • Whareroa Marae (Mount Maunganui)

None of the stations exceeded this threshold more than the allowed 9 times in a 12-month period.

Figure 2: Number of exceedances of the NESAQ’s lower threshold (350µg/m3, nine exceedances per 12-month period allowed), 2008-2017

Whareroa Marae (Mount Maunganui) and Woolston (Christchurch) exceeded the upper 570µg/m3 threshold of the national one-hour average standard twice each between 2008 and 2017). No exceedances of this threshold are allowed. Both sites are classified as industrial sites (i.e. close to industrial activities).

Six out of nine monitoring stations exceeded the 24-hour average WHO guideline of 20µg/m3 between 2008 and 2017 (Figure 3).

Totara St (Mount Maunganui), an industrial monitoring site, exceeded the guideline the most – 659 times between 2008 and 2017. Residential monitoring sites such as Timaru, St Albans (Christchurch) and Robert St (Whangarei) reported no exceedances.

Figure 3: Number of exceedances of WHO 24-hour average guideline (20µg/m3), 2008-2017

For more information about sulphur dioxide, please download the factsheet.

No breaches of carbon monoxide in 2013

Carbon monoxide levels at all 21 monitored sites met the national short-term (8-hour) standard (of 10 µg/m³) in New Zealand in 2013.  Many of these sites were peak sites, suggesting that carbon monoxide levels are low elsewhere also.

Carbon monoxide can harm health, by reducing the blood’s ability to carry oxygen. People with certain types of heart disease are at increased risk. 

Information about the data

Nitrogen dioxide

Source: Ministry for the Environment and Stats NZ - New Zealand's Environmental Reporting Series: Our air 2018. Data to 2017

Definition for indicator 'Monitoring sites exceeding the national environmental standard (one-hour average) for nitrogen dioxide: One-hour average sulphur dioxide concentrations (in µg/m3) are compared with the National Environmental Standard for Air Quality for nitrogen dioxide. The threshold is exceeded when concentrations are above 200µg/m3. The threshold is allowed to be exceeded nine times in a 12-month period.

Definition for indicator 'Monitoring sites exceeding the WHO annual average guideline for nitrogen dioxde': Annual averages are calculated and measured against the WHO annual average guideline. Exceedances occur when concentrations are above 40µg/m3.

Carbon monoxide

Source: Ministry for the Environment – New Zealand’s Environmental Reporting Series: Environment Aotearoa 2015

Definition: Number of monitoring sites exceeding the WHO long-term (annual) guidelines and national short-term standards for carbon dioxide. Only selected monitoring stations measure these air pollutants.

Sulphur dioxide

Source: Ministry for the Environment and Stats NZ – New Zealand’s Environmental Reporting Series: Our air 2018. Data to 2017 

Definition for indicator 'Monitoring sites exceeding the national environmental standard (one-hour average) for sulphur dioxide': One-hour average sulphur dioxide concentrations (in µg/m3) are compared with the National Environmental Standard for Air Quality for sulphur dioxide. The lower threshold is exceeded when concentrations are above 350µg/m3 and the upper threshold is exceeded when concentrations are above 570µg/m3. The lower threshold is allowed to be exceeded nine times in a 12-month period.  

Definition for indicator 'Monitoring sites exceeding the WHO daily guideline for sulphur dioxide': 24-hour averages are calculated and measured against the WHO daily average guideline. Exceedances occur when concentrations are above 20µg/m3.

References

1. Ministry for the Environment. 2011. 2011 User’s Guide to the revised National Environmental Standards for Air Quality. Updated 2014. Wellington: Ministry for the Environment.

2. Ministry for the Environment & Stats NZ. 2018. New Zealand's Environmental Reporting Series: Our air 2018: Data to 2017. Wellington: Ministry for the Environment.

3. WHO. 2013. Review of evidence on health aspects of air pollution – REVIHAAP Project. Copenhagen: WHO Regional Office for Europe.

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