Air Quality

Air quality in the Greater Wellington region is generally very good. Some areas have problems during winter mostly due to home heating. Exhaust gases from traffic degrade air quality one some of our busy city streets. We monitor air quality at five permanent sites across our region that are shown on LAWA and track trends in traffic-related air pollution using a network of low-cost sensors.

Everyone deserves to breathe clean air. The more that air pollution is reduced the better it is for our health. The two main sources of human-made air pollution that affect our health are particles (PM10 and PM2.5) from burning wood for winter home heating and exhaust gas from traffic (NO2).

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

Annual average NO2 levels measured at our residential sites in Upper Hutt and Masterton meet World Health Organization guidelines but are not met at our roadside monitoring site in Wellington. Our low-cost NO2 monitoring network (not available on LAWA) indicate that traffic-related air pollution in residential areas away from busy streets is generally low. However, levels of NO2 on some of our busier inner-city streets can be high when there are large numbers of diesel vehicles and where tall buildings either side of the street trap air pollution.

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 PM₁₀concentrations at selected sites. Trends are reported for towns where 10 or more years of PM₁₀ measurements are available. You can find PM_2.5 concentrations and exceedances reported at Wellington Central and Masterton sites and in the downloadable air quality dataset on the download data page.

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