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Odours - what a nuisance!

Most air quality complaints and enquiries that Waikato Regional Council receive are about odours. Find out where they come from, why odours affect people differently and why odours are difficult to manage. Find out what you can do if you have concerns about odour.
Photograph of pulp and paper processing. On this page: Different reactions to the same odour, Odour sources, Managing odour, Find out more

Odours are caused by mixtures of chemicals that stimulate our sense of smell. Unpleasant, strong, long-lasting odours can be a real nuisance, reducing our enjoyment of life.

Different reactions to the same odour

The best way of assessing odour is via the human nose. But everyone reacts to odours differently. One person may object strongly to an odour while another is not bothered by it. Some odours are pleasant, for example the smell of freshly mown grass, while others are considered highly offensive.

How much an individual reacts to odours can depend on the:

  • frequency of the odour – how often it occurs
  • duration of the odour and time of exposure – for example, some odours may only occur during standard work hours, while others are more constant
  • character and intensity of the odour
  • location of the odour – for example, rural, industrial, public area.

Sensitivity to odour can also vary according to a person’s:

  • age
  • perception/view of the emitter
  • mental state
  • other compounding issues (such as stress at work or home)
  • general state of health and wellbeing.

Cultural issues may mean that certain types of odour are not acceptable, for example, from a crematorium or sewage treatment plant.

Previous exposure to a certain odour means that some people may have become de-sensitised to it over time and no longer find it offensive. For example, people who have grown up in a town where a particular industry is the main employer, may generally accept odour emissions as part of life.

Odour sources

There are many sources of odour in the Waikato region including:

  • intensive indoor farming such as piggery and poultry farms
  • pulp and paper manufacturers
  • meatworks and rendering plants
  • skin and hide processing plants, such as tanneries, fellmongeries and wool-scourers
  • stockpiles of organic waste on farmland
  • commercial composting operations and landfills
  • wastewater treatment plants and spray irrigation of effluent
  • commercial food processing and preparation
  • agrichemical spray operations
  • domestic sources, such as composting and house painting.

Managing odour

Odour is complicated to manage because:

  • some people are more affected by odours than others
  • it’s very difficult to identify and measure odours, especially at low concentrations.

Odour emitters getting up your nose?

Waikato Regional Council encourages people concerned about odour to meet with those creating the odours to talk about their complaint. Most situations can be resolved this way. You’ll find that most people are reasonable, and willing to discuss the problem.

Remember that those causing the odour:

  • may not be aware that it’s a problem (desensitisation to the odour)
  • may not be aware of the exact cause of the odour.

Role of the Waikato Regional Council

The Waikato Regional Council responds to concerns about odour. While we encourage people concerned about odour to meet with those causing the odour, sometimes a solution cannot be agreed upon. The Waikato Regional Council then makes a preliminary assessment of the problem. This involves a site investigation to measure the:

  • frequency of the odour
  • intensity of the odour
  • duration of the odour
  • nature of the odour
  • location of the odour
  • any previous confirmed odour complaints relating to the same site.

If Waikato Regional Council determines a problem exists, we’ll encourage the nuisance emitter to control their odour discharges. If solutions cannot be found where both parties are happy, there will inevitably be winners and losers. In past cases determined by Waikato Regional Council, some have gone in favour of the complainant, while others were in favour of the emitter.

Following the preliminary assessment more information may be needed. We may:

  • Request that the emitter keeps a complaint register and responds to complaints to identify the sources or causes of objectionable odours.
  • Request that people living and working in the area keep a diary that notes the details of any objectionable odour event.
  • Carry out a public survey or field investigation to find out how widespread and how bad the odour is.
  • Require those causing the odour to test odour samples using people’s sense of smell to determine strength of the source.

Find out more

Find out about Waikato Regional Council's guidelines for assessing acceptable levels of odour for resource consent applications.