Particulate matter

This section provides monitoring data on particulate matter (PM10) levels in New Zealand, including long-term exposure (annual averages) and short-term exposure (daily levels). 

PM10 (particles with a diameter less than 10 micrometres) is the major air pollutant monitored in New Zealand. Exposure to particulate matter can contribute to heart and lung diseases, and can lead to hospitalisations and premature death.

Most PM10 health impacts are associated with long-term exposure. The World Health Organization's (WHO) annual average PM10 guideline is 20 micrograms per cubic metre (μg/m³). However, there is no evidence of a safe level for PM10.

On this page

Most monitoring sites met annual PM10 guideline in 2013

In 2013, most monitoring sites met the WHO’s guideline for annual average PM10 (45 out of 53 sites, or 85 percent) [1].  

There were eight monitored sites that exceeded the WHO annual guideline. Anzac Park in Timaru had the highest annual PM10 level (26.9µg/m3 ), followed by Alexandra (24.9µg/m3 ) and Woolston (24.4µg/m3 ) (Figure 1).

Figure 1: Monitoring sites that exceeded the annual average PM10 guideline (of 20 μg/m³) in 2013

     From 2006 to 2013, New Zealand’s annual average PM10 concentration at monitoring sites decreased by 8 percent, from 17.0 μg/m³ (at 38 monitoring sites), to 16 μg/m³ (at 53 monitoring sites). Higher annual PM10 concentrations in the South Island are generally due to greater use of wood and coal for home heating. Some towns also have relatively settled winter conditions, which mean less dispersion of pollutants.

Many urban areas exceeded daily limits of PM10 in 2013

In 2013, 21 of the 37 airsheds (57 percent) exceeded the daily PM10 standard (50 μg/m³) on 2 or more days.  This was down from a peak of 26 airsheds in 2008.

Among the airsheds exceeding the daily PM10 standard in 2013:

  • one airsheds exceeded the standard on 50+ days
  • two airsheds exceeded it on 21-50 days
  • six airsheds exceeded in on 11–20 days
  • 12 airsheds exceeded it on 2–10 days.

High levels of short-term PM10 can cause health effects within 24 hours, including respiratory problems.

International comparisons

New Zealand has a relatively low annual average PM10 level in urban areas by international standards.

In 2011, New Zealand had the 7th lowest level of PM10 concentration, out of 32 OECD countries [1]. New Zealand’s national annual average PM10 levels remain higher than some countries, including Australia and Canada.

Figure 2

Health effects of particulate matter

Particulate matter (PM10) can lead to premature death, and hospitalisations for cardiovascular (heart) and respiratory (lung) disease. Both long-term and short-term exposure to PM10 can affect health.

In 2012, there were an estimated 1000 premature deaths due to human-made PM10 in New Zealand [1]. This had decreased since 2006.  Read more on the health effects of air pollution webpage.

Information about the data

Particulate matter (PM10) – annual average and daily values

Source: Ministry for the Environment  – New Zealand’s Environmental Reporting Series: Environment Aotearoa 2015

Definition: Number of monitoring sites exceeding the annual average PM10 guideline level of 20 µg/m³; number of monitoring sites exceeding the daily (24-hour) maximum average PM10level of 50 µg/m³.

These data are taken from monitoring stations in these airsheds, and are published by the Ministry for the Environment [1]. In 2013, 53 monitoring sites measured PM10. In 2013, daily PM10 concentrations were measured in 37 airsheds (areas defined for air-quality management purposes, generally based around urban and city areas) [1].

Evidence linking PM2.5 to health effects is stronger than that for PM10 [2]. However, PM2.5 levels are not included as an indicator, as PM2.5 is currently only measured at a selected number of monitoring sites in New Zealand.

For more information on the National Environmental Standards for Air Quality, visit the Ministry for the Environment website.

References

1. Ministry for the Environment and Statistics New Zealand. 2015. New Zealand’s Environmental Reporting Series: Environment Aotearoa 2015. Available from www.mfe.govt.nz and www.stats.govt.nz.

2. World Health Organization. 2013. Review of evidence on health aspects of air pollution - REVIHAAP Project: Final technical report. Copenhagen: World Health Organization Regional Office for Europe.