1 Introduction
1.1 Purpose
Objectionable and offensive odours have the potential to cause significant adverse effects on people's lives and wellbeing. Complaints about odour emissions are one of the most frequent environmental pollution incidents reported to regulatory authorities.
Typically odours are managed under the Resource Management Act 1991 (RMA), although other legislation such as the Health Act may also be relevant. Odour management is complicated by a number of factors - the range of adverse effects it can cause, and people's varying sensitivity to odours, which can cause conflict between neighbours and odour producers about the severity of the effects. Conflict needs to be resolved by assessing the effect on neighbours and deciding what action is required to remedy any unacceptable effects. It is therefore important to have a well-debated national approach to assessing and managing odour so that the methods applied are consistent.
This Good Practice Guide for Assessing and Managing Odour in New Zealand suggests a national approach to assessing and managing offensive odours. It contains well-debated, expert advice for those involved in managing odour, including council staff, resource consent applicants and holders, councillors, consultants, and others who may be affected by odour. The key recommendations for good practice are summarised in boxes at the end of the relevant sections.
The guide contains advice on:
- how to assess the effects of odour, including how to determine what "no objectionable or offensive odour" means
- how to monitor the effects of odour through community surveys, odour diaries and council investigations
- case law developed under the RMA relating to odour management in New Zealand
- when to use dispersion modelling
- how to manage odour emissions, including some basic information on suitable mitigation options.
The guide updates the Ministry for the Environment's previous odour guide, Odour Management under the Resource Management Act, which was published in 1995 (Ministry for the Environment, 1995).
The process for producing this guide involved the development of a background technical report (the Technical Report) entitled Review of Odour Management in New Zealand: Technical Report (Ministry for the Environment, 2002c). The Technical Report formed the basis of the draft version of the guide (Ministry for the Environment, 2002a), which was released for public comment in September 2002. Both the Technical Report and draft guide were reviewed and consulted on during workshops and a formal peer review process. Submissions and comments at the workshops have been taken into account in producing this final guide.
1.2 Roles and responsibilities
Regional councils, unitary authorities and territorial councils all have certain responsibilities for managing emissions that may cause offensive odours. This section provides a brief overview of these roles and responsibilities. Further details of legislative matters are discussed in section 3.
Under the RMA, regional councils are responsible for managing discharges of contaminants into the air. They must consider the potential odour effects of discharges in the planning and resource consent process. Councils are responsible for monitoring compliance with resource consent conditions applied to odour discharges, and for responding to complaints about offensive odours. Councils will often encourage or facilitate discussions between the discharger and any affected communities. However, if there is no agreement and the issue cannot be resolved, then councils should ensure that the effects are assessed using the methods discussed in section 4 and appropriate action is taken in accordance with the RMA.
Territorial local authorities have both RMA and Health Act 1956 responsibilities. Under the RMA they are responsible for controlling land use and must consider the effect of land-use decisions on amenity values when planning and making decisions on resource consents. They are also responsible for preventing nuisances under the Health Act and can monitor and take enforcement action to abate nuisances. Territorial local authorities and regional councils should aim to work together to ensure there are no gaps or unnecessary overlaps in managing discharges to air.
Public health authorities have an advocacy role, but they have no direct regulatory function with respect to air emissions. They are able to advocate on behalf of the public when there is a health issue arising from a discharge, rather than a nuisance-type odour.
People with activities that discharge to air (dischargers) must comply with the requirements of the RMA, including section 17 (general duty to avoid, remedy or mitigate adverse effects), any relevant regional plan, or resource consent conditions. Dischargers have a duty to ensure that they are not adversely affecting people in the local community. They also need to demonstrate that they are taking appropriate action to comply with any council requirements within a reasonable timeframe or as specified by the plan or consent conditions.
Communication with the community is helpful to determine the main odour concerns and to decide appropriate mitigation measures if they are needed. Prior community discussion may also avoid the need for having to undertake detailed assessments using methods discussed in section 4. Because odour is an effect on people, the community should be involved in processes to determine and resolve odour issues, such as participating in community meetings, keeping diaries or making complaints. The public need to be sure they are genuine in their complaints, and not complaining for an ulterior purpose, bearing in mind that their view of what is acceptable will be judged in terms of the 'ordinary reasonable person', as discussed in section 3.3.1. Likewise, the public has the right to expect a reasonable response from regulators and dischargers when affected by an odour issue. Members of the public may take common law action if they are not satisfied with the response from a council or an industry.
When uncertainty and conflict increase between the industry and community, usually the time and cost required to resolve issues also increases. This guide recommends that dischargers are quick to investigate or acknowledge if there is a problem and work with communities to find solutions as a priority.
1.3 Status
The recommendations in this guide are not legislative requirements under the RMA or any other legislation. However, they are based on expert advice and consultation with practitioners involved in odour assessment, and regulators charged with managing offensive odours. As such they should be given reasonable weight in decision-making processes.
It is always difficult to recommend one set of procedures or assessment criteria for application on a national basis. Environmental impacts, especially those that are largely subjective such as offensive odours, can vary significantly on a case-by-case basis and procedures that might be right for one situation will not be appropriate for another. Users of the guide should bear this in mind and use the information and guidance reasonably, taking into account the specific circumstances of each case.
When in doubt about following any of the recommendations, it is appropriate to check with your local council. They will be able to tell you what information they need to make decisions and what criteria they are likely to use to determine whether an odour is offensive and objectionable, causing significant adverse effects. They can also explain their rules and requirements for resource consents.
