Limitations of the scientific basis for the management of air quality in urban New Zealand.

As enumerated by Ministry for the Environment, planned reductions in levels of air pollution in New Zealand sufficient to allow compliance with the National Environmental Standards for Air Quality will save, in a cost-effective manner, numerous lives per year. However, as indicated by careful study of the literature and of the methods employed to perform the relevant calculations, such claims are flawed. Instead of a precise number of deaths avoided, small changes in regional life expectancy are a more likely tangible consequence of compliance and, as such, are better suited to assisting calculation of the associated benefits and costs. Some basic data relevant to communities and regions potentially susceptible to the effects of 'poor quality' or inclement air are provided. These support the view that urban air pollution as officially measured and normally encountered in New Zealand nowadays probably has comparatively small substantive mortality consequences.