The 1997 report, The State of New Zealand’s Environment 1997, concluded that:
New Zealand is thought to have good air quality by international standards but this judgement is based on little, but increasing, monitoring. In some locations in our larger urban centres, however, there is evidence of ambient air quality at times exceeding New Zealand guideline limits for protecting human health. …
Instances of significant air pollution are caused by the combined effect of discharges from industry, small businesses and homes and the growing use of our vehicle fleet. ...
Regional councils have mechanisms available under the Resource Management Act to deal satisfactorily with the point source discharges, both large and small, but these mechanisms are unlikely to be as effective on vehicle emissions. (Ministry for the Environment, 1997, chapter 10.)
Improvements in air quality monitoring
Since 1997, the number of air quality monitoring sites in New Zealand has increased. Monitoring has shown that, across New Zealand, high levels of PM10 particulates caused by road traffic and winter home heating can affect both large urban areas and small settlements. These areas are now much better defined than in 1997, with the requirement to formally identify areas as gazetted airsheds. Regional PM10 particulate monitoring networks have been expanded and upgraded to ensure continuous monitoring where levels are of concern. Legislation has also been introduced to address air quality issues in specific locations.
Levels of carbon monoxide
The 1997 report identified concerns that elevated levels of roadside carbon monoxide were likely to increase as vehicle numbers increased. However, while the national vehicle fleet has continued to grow since the mid-1990s, carbon monoxide levels at many monitoring sites appear to have improved. This improvement is most likely a result of improved vehicle technology.
Ozone levels in Auckland, Hamilton, and Christchurch
In 1997 little ozone monitoring took place. This meant the extent of ozone pollution was not well understood. Since this time, monitoring in Auckland, Hamilton, and Christchurch (the areas of potential concern identified in the 1980s) indicates that ozone levels are not as high as those experienced in parts of Europe, and are unlikely to be a significant health problem.
New air quality regulations
Since the 1997 report, 14 national environmental standards have come into effect to improve air quality in New Zealand. They do so by setting maximum thresholds for five common ambient air pollutants, and introducing prohibition and design standards. This is a significant step forward in improving New Zealand’s air quality.
Present and future management
Today, the main focus for improving New Zealand’s air quality is on addressing PM10 particulate pollution from home heating and traffic in affected areas around New Zealand. A number of initiatives (such as the Warm Homes initiative) are under way to address emissions from home heating and ensure better health.
As the Resource Management Act 1991 is unlikely to be effective in controlling air pollution from traffic, other work is under way to minimise the impact of air pollution from road transport. This work includes the introduction of a visible smoke test for warrants of fitness or certificates of fitness, and the requirement for imported vehicles to meet certain emissions standards. Further reductions in air pollution from road transport are likely to result through improved emissions control equipment on imported vehicles.
Having put in place regular monitoring of air quality in managed airsheds, work will continue to track the effectiveness of the national environmental standards for air quality to ensure levels of PM10 particulates meet the target set for 2013.
Future work on improving air quality is likely to focus on developing a better understanding of PM2.5 levels around New Zealand.