Wellington Region

Air Quality

Air quality in the Greater Wellington region is generally very good. Some areas have problems during winter mostly due to home heating. The Greater Wellington Regional Council (GWRC) currently monitors air quality in five different areas of the region using six monitoring stations.

The main source of particle air pollution in the Wellington Region is smoke from home heating, but industry, traffic, rural fires and natural sources such as sea salt and dust can also influence air quality. Fires for home heating can lead to high levels of air pollution in some areas during winter.

Tiny particles from wood smoke and traffic can affect people's health. We measure levels of these particles using two indicators: PM10 and PM2.5. PM10 represents particles less than 10 microns across and PM2.5 represents particles less than 2.5 microns across. Greater Wellington currently monitors PM10 in five areas and in three of these areas PM2.5 monitoring is also carried out.

Annual average PM10 levels in all monitored areas are below national guidelines. Daily concentrations of PM10 don’t always meet the national standard during the winter in inland valley areas where home fires are common and when it’s cold, clear and still.

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.

We report on annual and daily PM10 and PM2.5 concentrations at selected sites. Trends are reported for towns where 10 or more years of PM10 measurements are available.

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