PM10 annual average concentrations

  • Image, PM10 annual average concentrations.

    2018 air indicators are now available

    Particulate matter 10 micrometres or less in diameter (PM10) in the air comprises solid particles and liquid droplets from both natural and human-made sources. In particular, it results from burning wood or coal for home heating, and from sea spray. PM10 is of particular concern because it is found in high concentrations in some areas and can damage health. It is associated with effects ranging from respiratory irritation to some forms of cancer.

    We classified PM10 annual average concentrations as a national indicator.

    Key findings

    Decreasing trend (improving state)

    From 2006 to 2013, the national annual average PM10 concentration fell 8 percent, from 17.4 μg/m3 (micrograms per cubic metre of air) to 16.0 μg/m3.

    • An increase in 2011 (up 0.4 μg/m3 from 2010) was influenced by higher concentrations in Christchurch as a result of the Canterbury earthquakes (due to dust generated by liquefaction, building damage, and reconstruction processes).
    • In 2013, 85 percent (45 of 53) of PM10 monitoring sites met the World Health Organization (WHO) long-term (annual) guideline.
    Note: The average concentration is population weighted to represent the population’s average exposure to PM10. By showing the concentrations at which 10 percent of sites are below and 10 percent of sites are above, the graph shows the range of concentrations that most sites (80 percent) experience. PM10 (particulate matter 10 micrometres or less in diameter) concentrations are in micrograms per cubic metre of air (μg/m3). WHO – World Health Organization. Data from regional councils of Northland, Bay of Plenty, Waikato, Hawke’s Bay, Manawatu-Wanganui, Wellington, Canterbury, West Coast, Otago, Southland; district councils of Marlborough and Tasman; Nelson City Council; Auckland Council.

    Definition and methodology

    Particulate matter 10 micrometres or less in diameter (PM10) can be emitted from the combustion of fuels, such as wood and coal (eg from home heating and industry), and petrol and diesel (from vehicles). Natural sources of PM10 include sea salt, dust, pollen, smoke (from bush fires), and volcanic ash. It is also formed from reactions between gases or between gases and other particles.

    The four main human-made sources of key pollutants in New Zealand are burning wood or coal for home heating, road motor vehicle use, industry, and household outdoor burning.

    See Relative contribution of key human-made emissions for more detail.

    This national indicator reports a population-weighted annual average concentration in micrograms per cubic metre (µg/m3). It is population weighted to take into account the populations exposed to the different concentrations. Approximately 65 percent of New Zealand’s population resides within monitored areas. The indicator does not account for unmonitored areas. Some of the monitoring locations are expected to have high concentrations (eg where home-heating emissions accumulate or are close to high-volume road traffic) and so may not be representative of the whole population they are assumed to represent.

    The long-term (annual) average concentration takes into account both peak and low-pollution periods and gives an indication of long-term health risks.

    Trend assessments are conducted on annual estimates and may not fully account for seasonal effects. The assessments do not indicate any underlying drivers behind the decreasing trend.

    Data quality

    We classified PM10 annual average concentrations as a national indicator.  


    This national indicator is a direct measure of the ‘Airborne particles of concern to human health’ topic.


    The accuracy of the data source is of high quality.

    See Data quality information for more detail.

    Supporting information

    Annual average PM10 concentrations in OECD countries 
    Annual average PM10 concentrations in towns and cities
    Total suspended particulate concentrations in Auckland


    Published 21 October 2015

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