Hazardous air pollutants

Sources of hazardous air pollutants and their effects on health. Usual levels in New Zealand and guideline values to protect human health.


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

Sources of hazardous air pollutants

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

Some of these hazardous substances are managed by the National Environmental Standards for Air Quality.

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.

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.

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.