Natural PM10

  • Image, Natural PM10.

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    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. PM10 occurs naturally, for example, as sea salt, dust (airborne soil), or pollen. Airborne soil particles, although natural, are also produced by human-made processes such as construction and industrial activities. Natural particulates can make up a large portion of PM10 in some areas.

    We classified Natural PM10 as a case study.

    Key findings

    Between 2006 and 2013, PM10 from airborne sea salt and soil contributed 28–55 percent of annual PM10 concentrations at some urban locations.

    • The annual average contribution of natural PM10 at a limited number of monitored locations ranged from 4 micrograms per cubic metre (μg/m3) in Blenheim to 13 μg/m3 in Dunedin.
    • Natural PM10 equates to between 18 and 63 percent of the World Health Organization (WHO) long-term guideline for allowable concentrations of PM10.
    • Sea salt made up between 39 and 87 percent of the natural PM10 at monitored locations.
    • Soil made up between 13 and 61 percent of the natural PM10 at monitored locations. (This measure does not differentiate soil emitted from natural and human-made activities).
    • Natural PM10 generally makes up only a small proportion of total daily PM10 concentrations that exceed the daily health standard. However, in some locations (on rare occasions due to storm events or volcanic activity) it can be a major component.

    Figure 1

    Note: Results do not necessarily represent the whole location. PM10 concentrations are in micrograms per cubic metre of air (µg/m3). Data from GNS Science; regional councils of Wellington, Hawke's Bay; Nelson City Council; Marlborough District Council; Auckland Council.

    Figure 2

    Note: Results do not necessarily represent the whole location. PM10 (particulate matter 10 micrometres or less in diameter) concentrations are in micrograms per cubic metre of air (µg/m3). Data from GNS Science; regional councils of Wellington, Hawke's Bay; Nelson City Council; Marlborough District Council; Auckland Council.

    Definition and methodology

    Soil particulates are natural materials that can arise from natural activities. However, they can also arise from human-made processes such as quarrying, demolition, construction, activities on unsealed surfaces (industry yards), and agriculture.

    Research on the health effects of natural particulate matter is inconclusive, and the World Health Organization (WHO) considers all particulate matter of a certain size to be of equal toxicity. Natural particulates are generally in the PM2.5 to PM10 size range, which typically has less harmful health effects than smaller particles.

    However, in a 2013 report the WHO commented that, overall, there is little evidence of the harmfulness of sea salt on human health. In contrast, there is evidence that soil (crustal matter, in the form of desert dust) may be harmful to human health. However, it is not yet clear whether crustal, human-made, or biological components of dust are most strongly associated with the effects.

    We measure the annual concentrations and proportions of natural and human-made PM10 (micrograms per cubic metre, μg/m3). The PM10 collected on filters is analysed to determine whether it is natural (sea salt or soil) or human made. The results we present include all studies conducted since 2006. We only include results that are annually representative.

    Data quality

    We classified Natural PM10 as a case study.

    Relevance

     This case study is a partial measure of the ‘Natural sources of particulate matter and other air pollutants’ topic.

    Accuracy

     The accuracy of the data source is of high quality.

    See Data quality information for more detail.

    References

    World Health Organization (WHO) (2013). Review of evidence on health aspects of air pollution – REVIHAAP project:  Final Technical Report. Available from www.euro.who.int.

     

    Published 21 October 2015

Related content

Access data files

PM10 data

 

Related indicators

PM10 annual average concentrations

PM10 daily concentrations 

 

Related links

Environment Aotearoa 2015

2014 Air domain report 

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