Manawatū-Whanganui region

Air Quality

Overall air quality in the Manawatu-Wanganui region is very good to good, thanks generally to its windy and exposed environment, dispersed and small population centres (we only have two cities, Palmerston North and Wanganui), relatively light industry and low vehicle numbers. In winter this quality is slightly degraded in the populated centres by the increase of fine particulate concentration from domestic heating units and outdoor burning.

Horizons Regional Council has two gazetted airsheds (Taihape and Taumarunui - they are small townships in the Central North Island) where it monitors fine particulate concentrations (PM10 and PM2.5). The towns were selected from a winter monitoring programme of the regions 12 largest urban areas from 2001 to 2003. PM10 and PM2.5 are contaminants that are typically associated with burning - domestic heating (open fires and woodburners), outdoor burning, industry and vehicle emissions, although natural sources such as dust, pollen and sea salt also contribute. Emissions from domestic heating units is the region’s main air contaminant of concern. The Regional Policy Statement focus for air is avoidance of unacceptable risks to human health and ecosystems, and achieving compliance with National Environmental Standards is a high priority. Emphasis is placed on controlling discharges from solid fuel burners and open fires, the main source of air pollution in our region, but also recognises the importance of controlling discharges from other sources such as transport and industry and also outdoor burning. Air quality is worst in urban areas where cold, calm conditions occur over winter and there is a large number of open fires and older woodburners.

Regional Summary

PM₁₀and PM_2.5at towns in this region

The most significant air pollutant in New Zealand are small airborne particles in our air (known as particulate matter). Particulate pollutants are of most concern in New Zealand because of their high concentrations in some of our towns. Exposure to high levels of airborne particle pollutants has the potential to cause respiratory and cardiovascular issues. View a factsheet on why air quality is important here.

PM10 and PM2.5 are the main contaminants of concern for Horizons with domestic heating the major source. This source contributes in excess of 80% to the winter fine particle concentrations (mean daily) in both Taihape and Taumarunui. Exposure to PM10 and PM2.5 can have short and long term health effects. We report on annual and daily PM concentrations each year.

PM monitoring history at towns in this region

Annual average
Highest daily average
Exeedance

Showing:

PM₁₀

Guideline

Concentration

% of guideline

What is this showing me?

The graph shows the annual average and highest daily average PM₁₀ concentrations, and number of exceedance days for the year selected. These are shown against air quality guidelines of 20 µg/m³ for annual averages and 50 µg/m³ for daily averages. The World Health Organisation published new guidelines in September 2021 of 15 µg/m³ for annual averages and 45 µg/m³ for daily averages. Values above the guidelines can be a cause for concern as exposure to high PM₁₀ values can cause short and long term health effects. The trends in the table below indicate whether the PM₁₀ concentrations have been improving, showing no measurable change, or declining over the previous 10-years. (For towns that have more than one monitoring site, a representative site is shown).

Data table PM₁₀

Towns	10-year Trend	annual average (µg/m³)	Highest daily average (µg/m³)	2nd highest daily average (µg/m³)	Number of exceedances

PM_2.5

Guideline

Concentration

% of guideline

What is this showing me?

The graph shows the annual average and highest daily average PM_2.5 concentrations, and number of exceedance days for the year selected. These are shown against air quality guidelines of 10 µg/m³ for annual averages and 25 µg/m³ for daily averages. The World Health Organisation published new guidelines in September 2021 of 5 µg/m³ for annual averages and 15 µg/m³ for daily averages. Values above the guidelines can be a cause for concern as exposure to high PM_2.5 values can cause short and long term health effects. The trends in the table below indicate whether the PM_2.5 concentrations have been improving, showing no measurable change, or declining over the previous 10-years. (For towns that have more than one monitoring site, a representative site is shown).

Data table PM_2.5

Towns	10-year Trend	annual average (µg/m³)	Highest daily average (µg/m³)	2nd highest daily average (µg/m³)	Number of exceedances

Towns 2

Towns in the Manawatū-Whanganui region

Select the town you'd like to see information on by clicking the buttons below or navigate using the map.

Taihape

1 Site

Taumarunui

1 Site