LAWA Air Quality - National Picture 2025

Published: 3 June 2025

 

Why air quality is important

Breathing clean air is fundamental to our wellbeing. The health impacts of air pollution are wide-ranging, with older adults, children, and other vulnerable groups being most at risk. Good air quality is also important for ecosystem health - for example, dust on plant leaves can reduce photosynthesis.

 

Air quality context in New Zealand

New Zealand has relatively good air quality due to its low population density and island geography. Over the past 15-20 years, the air pollutant of most concern in many parts of New Zealand has been particulate matter (PM) from burning wood and coal. Concentrations of PM have been reducing in most monitored areas.

The updated World Health Organization (WHO) Air quality guidelines (2021) and the Health and Air Pollution in New Zealand (HAPINZ 3.0) report (2022) reveal that health impacts from nitrogen dioxide – primarily from vehicle emissions - are more significant than previously understood.

 

What is monitored and shown on LAWA?

To help protect air quality, regional councils and unitary authorities monitor outdoor air for key air pollutants. Monitoring sites track air pollutants generated from different activities such as residential, industrial, and traffic sources.

LAWA shows air quality information from around 150 active and historical monitoring sites across New Zealand’s towns and cities. Many sites are in areas known or suspected to have poor air quality. Therefore, the data presented on LAWA are not nationally representative of overall air quality in New Zealand but instead provide localised insights into air quality and factors that contribute to air pollution.

 

Pollutants monitored

Commonly monitored air pollutants include:

• Particulate matter (PM): Tiny airborne particles, both naturally occurring (e.g. dust, pollen, sea salt) and human made (e.g. burning of fuels). Their health impact depends on particle size:

  • PM₁₀: Coarse and fine particles (less than 10 micrometres) that can enter our airways.

  • PM_2.5: Fine particles (less than 2.5 micrometres that can penetrate deep into our lungs, with the ultrafine particles (less than 0.1 micrometres) entering the bloodstream.

• Gas pollutants: Including sulphur dioxide (SO₂), carbon monoxide (CO), nitrogen dioxide (NO₂) and benzene, primarily monitored in cities where traffic and industry are often the main sources.

 

Reporting standards and guidelines

Air quality data are reported against standards and guidelines. The two main standards and guidelines used on LAWA are:

• National Environmental Standards for Air Quality 2004 (NES-AQ) – these regulations are made under the Resource Management Act to provide a minimum level of health protection for people in New Zealand. 

• World Health Organization Air quality guidelines 2021 (WHO 2021) – these are non-regulatory and informed by recent scientific understanding of health risks from air pollution.

 

Particulate matter - current state (2024)

In some parts of New Zealand, many people are exposed to relatively high PM levels during winter, primarily from home heating using wood and coal. In these areas, levels can exceed national air quality standards or guidelines, usually on colder winter days and nights when there is no wind to disperse the PM.

• PM₁₀ is the most commonly monitored air quality pollutant. It tells us about the particulate matter in the air including both the coarse particles (ranging from 2.5 – 10 µm in size) and smaller fine particles (PM_2.5, with a diameter of 2.5 µm or less).  

• PM_2.5 is mostly generated by combustion (e.g. burning wood, coal and diesel) and is likely to be more harmful. Measuring PM₅enables us to better understand which areas pose higher health risks compared to measuring PM₁₀alone.

Where both both PM₁₀ and PM_2.5 are monitored, results show that PM_2.5 concentrations often make up a large proportion of the PM₁₀ concentration when combustion sources are present.

 

Key findings

• Daily average PM₁₀ concentrations: 40 of 55 sites met the daily NES-AQ across eight of the 15 monitored regions (Figure 1).

• PM_2.5: Six of 35 sites met the daily WHO 2021 guideline (Figure 1). There were three monitoring sites that met both the daily and annual WHO guidelines for PM_2.5 - Whareroa Marae in Mount Maunganui, Whangārei, and central Wellington.

• The highest PM_2.5 annual average concentrations were observed in towns such as Tokoroa, Pūtāruru, Kaiapoi, and Timaru, where winter woodsmoke from home heating is trapped by local topography and weather conditions.

 

LAWA National Air Quality State (2024)

Figure 1: Comparison of monitored sites that met or did not meet the daily PM₁₀ standard (NES-AQ) and PM_2.5 guideline (WHO 2021) in 2024. The location of sites, and whether they met the daily PM₁₀ standard or PM_2.5 guideline, are shown on the maps.

 

Note: The World Health Organization (WHO 2021) guidelines are more stringent than the previously reported WHO 2005 guidelines. The newer guidelines are based on improved understanding of the health impacts of breathing in fine particles. As a result, more PM_2.5 sites exceed the new guidelines compared to earlier reporting against the 2005 guidelines. The WHO advises the vast majority of the world’s population breathes air that exceeds the guidelines for PM_2.5. Although many councils monitor and report on PM_2.5, it is not currently a regulatory requirement in New Zealand. The Ministry for the Environment is considering how best to include PM_2.5 in future regulations. We expect monitoring coverage for PM_2.5 to increase in coming years, and these sites will be displayed on LAWA.

 

How has air quality (particulate matter) changed over time?

 

Key findings

• Most monitored towns and cities show improved air quality over the last ten years (2015–2024). Thirty of the 44 monitoring sites where there was enough data for trend analysis showed improving air quality (Figure 2).

• Ten sites had an indeterminate trend. This means there is not enough statistical certainty to determine if the air quality has been improving or degrading.

 

LAWA National Air Quality PM₁₀ 10-year Trends (2015-2024)

Figure 2. Ten-year trend results at sites monitored for PM₁₀ using data from 2015–2024. The location of these sites and trend result is shown on the map. Eleven sites did not have enough data available to calculate a 10-year trend and are not included in the results. This happens when monitoring started after 2015, there are large data gaps, or there were changes to the monitoring instruments.

 

Of the 40 monitoring sites that met the national standards (NES-AQ) for PM₁₀ in 2024, 22 sites (or 55%) have had improving air quality, two sites (or 5%) had declining air quality, and eight sites (20%) had indeterminate trends. The remaining eight sites did not have enough data available to calculate a trend.

Of the 15 monitoring sites that did not meet the NES-AQ for PM₁₀ in 2024, eight sites (or 53%) have had improving air quality, and two sites had declining air quality over the last 10 years. The trend was indeterminate at two sites, and three sites did not have enough data to determine a trend.

 

Gas pollutants

Gas pollutants are primarily monitored in urban areas where traffic and industry are often the main sources. The levels of gas pollutants typically meet the national standard (NES-AQ). However, levels of nitrogen dioxide (NO₂) are usually higher and do not meet the WHO 2021 guidelines near major transport corridors in larger cities. Nitrogen dioxide monitoring results can be found at sites in Auckland, Mount Maunganui, Hamilton, Wellington, Masterton, Christchurch, Ashburton and Timaru.

The NZ Transport Agency Waka Kotahi has an extensive monitoring network on state highways around New Zealand. More information can be found here.

 

Air quality monitoring and reporting

Air quality data help scientists and decision-makers to understand local air quality, identify what impacts it, and how it is changing over time. This informs the policies and actions needed to improve air quality and benefit people's health. When PM₁₀ standards are exceeded, councils notify the public and work towards improving the air quality.

 

Explore more on LAWA

• Click on the Regions tab to explore summary information for each region. Then click Towns to explore seasonal changes and find out about the main contributors of air pollutants.

• For individual monitoring sites, select a dot on the map (desktop and tablet users), or navigate through menus (region → town → monitoring site).

• The organisation responsible for monitoring an individual site can provide further context to the results in their region. 

 

National environmental reporting on air quality

The Ministry for the Environment and Stats NZ provide national reporting under the Environmental Reporting Act 2015. Our air 2024 was published on 9 October 2024.

Our air 2024

 

Stats NZ collect information to publish insights and data about New Zealand, including environmental indicators of air quality.

Stats NZ: Air indicators

 

The HAPINZ 3.0 report was released by Ministry for the Environment, Ministry of Health, Ministry of Transport, and NZ Transport Agency Waka Kotahi on 6 July 2022. HAPINZ 3.0 is the latest update of this report series and assesses the air pollution health impacts experienced by New Zealanders for 2016. A significant finding was that of the more than 3,300 deaths associated with anthropogenic air pollution, more than 60% were associated with nitrogen dioxide (NO₂) pollution – largely from motor vehicles, while the other 40% were associated with fine particulate (PM_2.5) pollution – mostly from home wood burning. The report acknowledged the overall improvements in PM levels and the increase in regional and unitary council monitoring of PM since the previous HAPINZ 2.0 report.

HAPINZ 3.0 report

 

What can I do?

We all contribute to air quality and can help improve it by:

• Using clean heating methods

• Burning wood responsibly (smokefree)

• Avoiding outdoor burning

• Reducing vehicle emissions

• Reporting pollution to your local council