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. 1 May 2023: Please note that due to sensor failure, PM2.5 data is not currently available in the graph below.

PM monitoring history at towns in this region

Annual average
Highest daily average
Exceedance

Showing:

PM₁₀

What is this showing me?

The graph enables you to view the annual average and highest daily average concentrations of PM₁₀ and number of exceedance days for the year selected. The results are compared to the relevant air quality standard or guideline (denoted by the red horizontal line). See this factsheet for more information about the PM₁₀ measurements, and the standards and guidelines used to report on.

Values above the standard or guideline shown can be a cause for concern as short- or long-term exposure to high PM₁₀ can have health impacts. See this factsheet about why air quality is important and factors that influence air quality.

The trends in the table below indicate whether the PM₁₀ concentrations have been improving, showing no measurable change, or declining over the 10-years prior to the year selected. (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

What is this showing me?

The graph enables you to view the annual average and highest daily average concentrations of PM_2.5 and number of exceedance days for the year selected. The results are compared to the World Health Organization guidelines (denoted by the red horizontal line). See this factsheet for more information about the PM_2.5 measurements, and the standards and guidelines used to report on.

Values above the guidelines can be a cause for concern as short- and long-term exposure to high PM_2.5 values can have health impacts. See this factsheet about why air quality is important and factors that influence air quality.

Any trends in the table below indicate whether the PM_2.5 concentrations have been improving, showing no measurable change, or declining over the 10-years prior to the year selected. (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