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Hazardous air pollutants

This page provides information on sources of hazardous air pollutants and their effects on health. It includes usual levels in New Zealand and guideline values to protect human health.

This page has not yet been updated to reflect changes as a result of Our air 2018 report.


There are many potentially hazardous air pollutants  including:

dioxins and polychlorinated biphenyls (PCBs) xylene mercury
benzene toluene chromium
polycyclic aromatic hydrocarbons (PAH) styrene arsenic
1,3-butadiene formaldehyde lead
acetaldehyde benzo(a)pyrene  


Hazardous air pollutants are released from activities such as:

burning waste (including plastics, medical and hazardous waste) smoking using solvent base paints

oil refining

motor vehicles
landfill fires spray painting fibreglass manufacture particle board mills application of agrichemicals
burning wood or coal for home heating synthetic rubber manufacture adhesive manufacture    

Effects on health

Hazardous air pollutants can affect human health in a number of ways including skin, throat and eye irritation, headaches, nerve and organ damage, and increased risk of cancers and premature death.

This usually happens when the pollutants are breathed in over long periods of time as they can accumulate in our bodies. However some hazardous air pollutants can have a more immediate effect. 

The Ambient air quality guidelines: 2002 update includes more information on the health effects of each pollutant.

Guideline values to protect health

The New Zealand guideline values for nine priority hazardous air pollutants are:

Contaminant Guideline value Averaging time
Benzene (year 2002) 10 µg/m3 Annual
Benzene (year 2010) 3.6 µg/m3 Annual
1,3-Butadiene 2.4 µg/m3 Annual
Formaldehyde 100 µg/m3 30 minutes
Acetaldehyde 30 µg/m3 Annual
Benzo(a)pyrene 0.0003 µg/m3 Annual
Mercury (inorganic) 0.33 µg/m3 Annual
Mercury (organic) 0.13 µg/m3 Annual
Chromium VI 0.0011 µg/m3 Annual
Chromium metal and chromium III 0.11 µg/m3 Annual
Arsenic (inorganic) 0.0055 µg/m3 Annual
Aresine 0.05 µg/m3 Annual
Lead 0.2 µg/m3 3 month moving average

See the Ambient air quality guidelines: 2002 update for further information on the application and intended use of the guideline values.


Hazardous air pollutants released into the air during spraying of agrichemicals in orchards can be hazardous if the spraying is not done correctly.

Usual levels in New Zealand

Research and monitoring shows that hazardous air pollutant levels in New Zealand are generally low.  However, there are some places where levels do pose a risk to human health. Further monitoring is needed to fully understand the effects of hazardous air pollutants on New Zealanders and our environment.

For more information on levels of some hazardous air pollutants see Environment Aotearoa 2015. 

Your local regional or unitary council may also have further information [Department of Internal Affairs website]

Areas where hazardous air pollutants may affect health

around discharges
urban areas where there are high concentrations of domestic fires or traffic