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Improving New Zealand's air quality

National environmental standards and guidelines

In 2004, national environmental standards (NES) for ambient (outdoor) air quality were introduced in New Zealand to provide a guaranteed level of protection for the health of New Zealanders. National standards for the pollutants reported on in this report card are set out in table 1 below.

Table 1: National air quality standards (2004)
Pollutant Standard – concentration limit Time average Allowable exceedances per year
Carbon monoxide (CO) 10 mg/m3 8-hours* 1
Nitrogen dioxide (NO2) 200 µg/m3 1-hour 9
Sulphur dioxide (SO2) 350 µg/m3
570 µg/m3
Ozone (O3) 150 µg/m3 1-hour 0

* Running mean

Text box 2: Exceeding and breaching the standards

The standard for a pollutant is exceeded whenever a monitored result is above the concentration limits provided in table 1. A breach occurs when the standard is exceeded more than the number of allowable exceedances per year.

Before the introduction of the national environmental standards, air quality was measured against the national air quality guidelines. The national guidelines were developed in 1994 and revised in 2002 following a comprehensive review of international and national research and remain relevant. The national guidelines for the pollutants reported on in this report card (where they differ from table 1), are set out in table 2 below.

Table 2: National ambient air quality guidelines (2002)
Pollutant Guideline – concentration limit Time average
Carbon monoxide (CO) 30 mg/m3 1-hour
Nitrogen dioxide (NO2) 100 µg/m3 24-hour
Sulphur dioxide (SO2) 120 µg/m3 24-hour
Ozone (O3) 100 µg/m3 8-hour

In 2006, the World Health Organization (WHO) published its first global air quality guidelines. The guidelines aim to improve air quality around the world to protect people's health and were developed by reviewing the information on the health effects of each pollutant. The WHO guidelines for the pollutants reported on in this report card (where they differ from tables 1 and 2), are set out in table 3 below.

Table 3: World Health Organization guidelines (2005)
Pollutant Guideline – concentration limit Time average
Sulphur dioxide (SO2) 20 µg/m3 24-hour
Nitrogen dioxide (NO2) 40 µg/m3 1-year

Improving home heating

Assistance to reduce the ambient emissions caused by home heating has been offered through national and local initiatives. Some examples of this assistance include free home energy audits, subsidies for cleaner heating options and installation of insulation, and information on how to operate wood burners efficiently.

The national environmental standards for air quality include performance standards for new wood burners to ensure they are clean and efficient. Since 2005, this has required all new wood burners in properties less than 2 hectares to meet specifications outlined in the standards. At the time of publication of this report card, six regional councils and/or unitary authorities have additional, in some cases more stringent, rules for wood burners in their regional plans. These councils are Auckland Regional Council, Hawke’s Bay Regional Council, Nelson City Council, Tasman District Council, Canterbury Regional Council and Otago Regional Council.

Improving emissions from vehicles

Since 2004, all vehicles entering New Zealand were required by the Vehicle Exhaust Emissions Rule to be manufactured to an approved emissions standard. The aim of the Rule was to reduce harmful exhaust emissions (carbon monoxide, oxides of nitrogen, hydrocarbons and particulates) from vehicles. In 2007, this rule was amended requiring vehicles entering New Zealand to meet more stringent emissions standards.4

Since 2006, as part of obtaining a warrant of fitness or certificate of compliance, all vehicles are required by the Vehicle Exhaust Emissions Rule to pass a visible smoke test.5

Improving fuel quality

In 2002, the New Zealand Petroleum Products Specifications Regulations were revised to reduce the sulphur content and the content of other pollutants in petrol and diesel fuels, with the aim of reducing harmful exhaust emissions from vehicles.

In 2004, 2006, and in 2009, the sulphur content of diesel was further reduced to a level where New Zealand’s diesel fuel is now termed ‘sulphur free’. Routine sampling of petrol and diesel occurs to ensure these fuels comply with the Regulations.6

The reductions in the sulphur content of diesel fuel have allowed newer diesel models that emit lower levels of pollutants into New Zealand’s vehicle fleet. Previously these models could not cope with the high sulphur content of diesel fuel in New Zealand.

Text box 3: Public perceptions of air quality

In a national public perceptions survey conducted in 2008, those surveyed indicated they thought New Zealand had good air quality. However, survey results over time indicate that the public believe New Zealand’s air quality has worsened over time, although the perception is that the management of air quality has improved. Those surveyed identified ‘motor vehicles and transport’ and ‘industrial activities’ as being the main pressures on air quality.7