Air quality is important, not just for our tourist appeal, but for our quality of life, our ecosystems and our health. Visitors often comment on the clarity of New Zealand's air, especially in rural, coastal and wilderness areas. But most New Zealanders live in cities and towns where, sometimes, the air can be less appealing. Although some aspects of urban air quality (e.g. lead levels, and smoke levels in Christchurch and Dunedin) have improved over the past 20 years, recent surveys indicate that some others are still a source of problems (e.g. particulate matter from domestic fires and carbon monoxide from home fires and motor vehicles). The surveys also indicate that the problems are not confined to big cities but extend to some smaller urban areas.
The potential health impacts of ambient air pollution are amplified for people with lung and heart conditions, and, aggravated by indoor pollutants, such as tobacco smoke and malfunctioning fireplaces. A quarter of the population is addicted to tobacco, even though they now consume less than in previous years. In many homes non-smokers (often children) are also exposed to the smoke. Bronchitis and emphysema, as well as elevated heart and cancer risks, are common in older smokers, making them more vulnerable to the effects of ambient air pollution.
Domestic fires are still the main source of air problems, both indoors and out, particularly where high-sulphur, high-ash, fuels are burned in low-efficiency open fires. At this point, it is difficult to gauge whether industrial sources are also contributing to air quality problems as the process of issuing and monitoring air discharge permits is still relatively new.
Carbon monoxide pollution from motor vehicles may be a growing problem in inner cities, particularly where high traffic density and low wind speeds allow fumes to build-up. Motor vehicle numbers are rising, encouraged by the dispersed, low density, design of most of our cities. These cities have grown up around the availability of motor vehicles and their public transport systems are often under-utilised.
Air emissions homes and vehicles are harder to manage than those from industry. Under the Resource Management Act, regional councils can limit air emissions from industrial and trade premises to the extent they consider necessary and can set ambient standards for emissions. This new system is currently evolving but it has the potential to effectively manage all industrial and trade discharges. At present, some industrial emissions are still uncontrolled while the Act is in its transitional phase. Councils also have the ability to impose controls on domestic fires (such as banning open fires and only allowing certain low emission burners).
Apart from regulations that ban the sale of leaded petrol and make it an offence for vehicle emissions to obstruct visibility, there are no environmental controls on motor vehicle emissions. Use of the Resource Management Act by regional councils is unlikely to be the most cost effective way to manage vehicle emissions. Other possible management options are under study in the Vehicle Fleet Emissions Control Strategy that is being developed by government officials under the leadership of the Ministry of Transport.
For the quality of our air to be well managed, we need better information than we have relied on in the past. With New Zealand's history of generally good air quality, authorities in most parts of the country have not felt the need to invest in the programmes and equipment which are required to regularly monitor air pollutants and record changes over time. Most of our air quality monitoring has been sporadic and uncoordinated, and often triggered by specific problems.
As a result, the approaches used in the rest of the world for managing air quality have not yet evolved here. Inventories of emissions, regional models for atmospheric dispersion, and strategies for managing air quality are now in the rudimentary stages of development in Auckland and Christchurch. Little basic research has been undertaken on the health impacts of air pollution in New Zealand, and none at all on the non-health impacts, such as visibility and ecological implications.
Despite these limitations, however, the initiatives currently underway by central government, Crown Research Institutes and the regional councils are positive steps. The production of a national database and a national set of air quality indicators should enable us, for the first time, to identify the extent of our clean and dirty air. And the development of monitoring guidelines for regional councils should enable them to keep better track of the trouble spots and deal with them effectively.