KEY POINTS:
Aucklanders can breathe easier - the Ministry for the Environment says the city's air quality is on track to meet health guidelines by 2013.
A report card released by the ministry yesterday shows air quality in cities the length of the country regularly breached daily standards for the amount of dangerous pollution in 2007.
But for the first time since monitoring began a decade earlier, air quality in all five main centres - Auckland, Wellington, Hamilton, Christchurch and Dunedin - met national guidelines for the amount of air pollution over a year.
Breathing air heavy with particulates - mostly released by people burning wood and coal for home heating, and transport in Auckland - is thought be responsible for about 1,100 premature deaths in urban areas each year, and to cost around $1 billion in illness and sick days.
Regional councils have until 2013 to bring levels of particulate matter, or PM10, in the air to within national health guidelines.
Yesterday, Ministry for the Environment spokesman Todd Krieble said Auckland was on track to meet that target. In 2007, Auckland breached air-quality standards seven times.
By 2013 it is allowed only one breach a year.
Niwa's group manager of urban air quality, Guy Coulson, said Auckland's air quality was on a par with London's, despite having far fewer people.
But schemes to reduce the number of wood- and coal-burning stoves were helping to improve air quality, he said. Some sources of particulate matter, such as dust and sea salt, were caused by the weather and so were beyond councils' control.
New Zealand's air-quality standards are based on recommendations from the World Health Organisation. Regional councils monitor 40 sites, known as airsheds, where air quality is likely to be poor.
In 2007, 42 per cent of airsheds complied with daily standards for levels of PM10 - up from 31 per cent in 2005.
Airsheds in Otago, Timaru and Rotorua breached the standards the most often; 81 per cent of airsheds met guidelines for the amount of PM10 in the air over a year.
An air-quality report for 2008 is due to be released towards the end of this year.