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Air pollution and visibility

There is no doubt that having good visibility is a valuable resource for New Zealand. Clear air is an excellent indicator of environmental quality, and one which most people can readily understand. The New Zealand community has come to expect good visibility and it is one of the reasons why tourists find this country attractive.

What is degraded visibility?

Degraded visibility is most simply described as haze that obscures the clarity, colour, texture, and form of what is seen through the atmosphere. It is a complex phenomenon influenced by a number of emissions and air pollutants, and affected by a number of natural factors such as temperature, humidity, meteorology, time and sunlight.

The Ministry’s work focuses on visibility degradation caused primarily by tiny particles suspended in the air and by gases such as nitrogen dioxide. These particles and gases scatter or absorb light, thereby reducing visibility and causing haze. A variety of sources, both human and natural, produce pollutants responsible for reducing visibility.

Why is visibility important for New Zealand?

New Zealand is fortunate in that visibility is still excellent in many areas for most of the time. However this may not always be so. Already there are perceptions that our air quality is degrading to unacceptable levels in the major cities, and noticeably in some scenic vistas. Protecting visibility in New Zealand is important for both maintaining environmental quality and for enhancing the amenity value of the environment for the community and tourists. It is an important component of our clean, green image.

What is the Ministry doing?

In August 2001, the Ministry published a good practice guide for monitoring and management of visibility in New Zealand. This guide provides information on:

  • the value of visibility in New Zealand
  • factors which affect visibility
  • monitoring visibility
  • visibility management
  • visibility protection.

Last updated: 17 September 2007