Sources of Air Quality Data
There is no doubt that the level of air quality monitoring in New Zealand is low compared to that carried out in other countries (Fisher, 1996). The reasons for this are, perhaps, justifiable in that New Zealand has often been perceived as having few air quality problems, and the population (and thus the tax base) is relatively low.
Although the first published reports relating to air pollution in New Zealand can be traced back to the end of last century, detailed air quality studies did not come until the mid- to late 1950s when they were needed to address specific problems in Christchurch and Auckland.
Christchurch had a problem with wintertime air pollution caused mainly by the smoke and sulphur dioxide from domestic fires and motor vehicles. In Auckland, the main concern was the smelly 'rotten egg' gas, hydrogen sulphide, emitted from the Manukau mudflats, although there were also some problems with a few local industries.
Although the hydrogen sulphide problem in Auckland effectively vaporised with the diversion of industrial liquid wastes to the new Mangere sewage plant in 1961, the sewage plant itself began to cause problems. The plant has been the cause of odour complaints almost from the time it opened, though to a much lesser degree than the original Auckland 'fumes'.
The wintertime problem in Christchurch also lingers on despite the fact that sulphur dioxide levels have dropped markedly over the last three decades with the significant overall reduction in coal and oil consumption, and the controls on the use of high-sulphur coals and the declaration of Clean Air Zones in Christchurch under the Clean Air Act 1972. Smoke levels have gone down as well.
These problems triggered the first air monitoring programmes in both cities. The programmes still operate but in substantially different forms. In both cases measurements were taken frequently for about the first five years. They were continued at a reduced level as the situation became better understood and resources were directed at other air pollution issues, such as carbon monoxide from motor vehicles.
Monitoring activity expanded after the Clean Air Act was passed in 1972. Studies were undertaken in a number of centres around the country, although many of the measurements were at a fairly basic level and were continued for only a few years. More intensive investigations of wintertime pollution were again carried out in Christchurch, while in Auckland the potential for photochemical smog was given a significant amount of attention. Specific programmes were also established around some of the larger industries throughout the country as these came under the control of the Clean Air Act.
By the end of the 1970s, much of the above effort had been scaled down once again, with routine monitoring mainly confined to a few sites in Auckland and Christchurch, and some of the industrial programmes. This situation was maintained throughout the 1980s with only two major changes: the addition of two routine monitoring sites in Dunedin, and the development of a national lead survey based on sites in Auckland, Hamilton, Palmerston North, Lower Hutt, Wellington, Christchurch and Dunedin.
The early air pollution investigations in Auckland and Christchurch were carried out under the auspices of the Auckland Air Pollution Research Committee and the Christchurch Air Pollution Advisory Committee. Both of these bodies were established by the various local and regional authorities at that time. From the mid-1960s, much of the above work was carried out either by, or at the request of, staff of the Department of Health. The Department funded the operation of three long-term air monitoring sites, to provide data for the World Health Organisation's Global Environmental Monitoring System (GEMS). Two sites were located in Auckland (Penrose since 1964 and Mt Eden since 1983) and one in Christchurch (at Packe Street in St Albans since 1987).
With the passing of the Resource Management Act in 1991, the day-to-day responsibility for air pollution control has now been transferred from the Department of Health, and city and district councils, to regional councils. This is leading to a resurgence of interest in air quality monitoring as regional councils implement their responsibilities to monitor as required by Section 35 of the Act.
A consequence of the new regime is that, despite the increased interest, air quality monitoring has been very uncoordinated (Fisher, 1996). Even so, both central government and regional authorities do have a few valuable monitoring programmes that gather data on the common pollutants identified in the ambient air quality guidelines developed by the Ministry for the Environment (see Table 6.1).
During 1995-96, the Ministry for the Environment's National Environmental Indicators Programme set up a working group to develop national indicators of air quality. The group involves representatives from regional councils, industry, universities and community organisations. The indicators are being developed to assist councils in defining their air monitoring needs and to also meet the needs of central government in tracking changes in environmental quality.
Emission inventories
As the monitoring of air quality begins to improve, attention is also turning to the monitoring of actual emissions. Air quality management would be enhanced if emissions data existed because the impact of sources would be more readily determined. This would enable air quality managers to assess how air quality may change with time, and develop cost effective control strategies.
The Christchurch Regional Council conducted a vehicle emissions testing programme from 1993 to 1995. Prior to this initiative, a number of surveys of fuel usage had been carried out in Christchurch in the previous 30 years, but the methodology was not particularly rigorous. Similar surveys were carried out in Auckland and Hamilton over 20 years ago. A reasonably comprehensive emission inventory was conducted in Auckland in 1976, and a more limited one was carried out in 1988. None of these allow us to make any definitive statements about the changes in total emissions over time.
The research on vehicle emissions has not been matched by similar research on household fire emissions. Although the Resource Management Act makes regional councils responsible for monitoring air quality, nobody is undertaking basic research on home heating emission rates. Typical emission factors have yet to be identified for given types of solid fuel and fireplace and, in addition, it is hard to obtain accurate data on firewood use.
