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Good Practice Guide for Assessing and Managing Odour in New Zealand

Foreword

Acknowledgements

1 Introduction

2 Properties and Effects of Odour

3 Legislation and Case Law

4 Odour Assessment

5 Odour Management and Control

Appendix 1: Odour Assessment Decision Trees

Appendix 2: Sample Survey Questionnaire

Appendix 3: Odour Management Plans

Appendix 4: Example Odour Diary Record Sheet

Appendix 5: Odour Control Systems

Appendix 6: Odour Thresholds for Individual Chemicals

References

About the Ministry

3 Legislation and Case Law

3.1 Relevant legislation

The Resource Management Act (RMA) is the primary piece of legislation under which odour discharges are regulated in New Zealand. The Health Act contains provisions relating to nuisances (section 29) that can be enforced by city and district councils where anyone permits or causes a nuisance.

The Health Act enables territorial authorities to appoint health officers and make bylaws to secure the abatement of nuisances that are likely to be injurious to health or that are offensive. However, the fines and other enforcement provisions available under the RMA mean that this has tended to assume greater importance than the Health Act.

This section focuses on the legislative basis for odour management, key definitions, regulatory responsibility and case law that has been established under the RMA.

3.2 RMA definitions

3.2.1 Purpose of the RMA

Section 5(1) sets out the purpose of the RMA, which is "to promote the sustainable management of natural and physical resources". Section 5(2)(c) provides for this to occur while "avoiding, remedying, or mitigating any adverse effects of activities on the environment".

Section 2 of the Act defines 'environment' and 'amenity values' as follows:

Since offensive odours can be considered to cause effects on amenity values, people and communities, they can be managed under the RMA.

3.2.2 Section 9: Use of land

Section 9 of the RMA provides that a person may use land in any manner they like provided it does not contravene a rule in a plan. If the activity contravenes a rule then a resource consent is required, except when existing use rights apply. The production of odour from a land use is not controlled by a district plan unless the plan includes restrictions on the effects of land uses that cause odour emissions.

3.2.3 Section 15: Discharge of contaminants

The compounds that cause odour effects are air contaminants, therefore their discharge is controlled under section 15 of the RMA. Under section 15(1) discharges from industrial or trade premises are only allowed if they are authorised by a rule in a regional plan, a resource consent, or regulations. If the activity is prohibited under the plan then no resource consent can be obtained. [Section 418 transitional provisions of the RMA carried over the licensing schedules under the (now repealed) Clean Air Act until plans could be developed. Most regional and unitary councils have a proposed or operative plan under the RMA, so section 418 is no longer relevant for most air discharges.]

Under section 15(2) the opposite presumption applies to discharges from any other source. Unless these sources are controlled by a rule in a plan, discharges are allowed as of right and resource consent is not required.

3.2.4 Section 17 and enforcement provisions

Section 17 of the RMA imposes an overriding duty upon every person to avoid, remedy or mitigate any adverse effect on the environment. The duty can be enforced by enforcement orders or abatement notices to require a person to cease doing something that is or is likely to be noxious, dangerous, offensive or objectionable to such an extent that it has or is likely to have an adverse effect on the environment. Relevant enforcement provisions are sections 314(1)(a)(ii) and 322(1)(a)(ii).

Odour emissions are typically classed as being objectionable or offensive to the extent that they are adversely affecting the environment. Odours do not normally become directly harmful to people's health because this usually only happens when the chemicals within an odour reach very high concentrations, much higher than their odour threshold. This is not to say that odours do not cause serious effects if individual compounds within them are below their health effects thresholds. 'Avoiding objectionable and offensive effects' is often used in resource consents and regional and district plans to describe the minimum requirement for an air discharge potentially resulting in odour.

3.2.5 Regulatory responsibilities for odour

Odour is produced both as a result of the use of land and from discharges to air, land or water and can therefore be covered by sections 9 and 15 of the RMA, as discussed above. Section 30 of the RMA specifies regional council functions including the control of discharges into or onto land, air or water and discharges of water into water. Section 31 covers the functions of territorial authorities, including the control of any actual or potential effects of the use, development or protection of land.

There are clearly options for integrated management between regional and district councils and the focus should be on integrating requirements in plans and joint decision-making. To ensure that there are no gaps in the management of odour or any duplication of effort, a clear protocol between territorial authorities and regional councils about their roles is recommended, and information sharing and discussions should take place regularly. Advice on dealing with conflicts and overlapping functions in rural areas can be found in Managing Rural Amenity Conflicts (Ministry for the Environment, 2001b).

3.3 Case law principles

This section summarises some principles that have been considered or established in case law under the RMA, and which are relevant to odour management. The principles that apply are often specific to a particular set of circumstances and no one 'rule' will apply to all cases. A full summary of the cases quoted can be found in Appendix 2 of the Technical Report (Ministry for the Environment, 2002c).

3.3.1 Objectionable and offensive

The legal context for the terms 'objectionable' and 'offensive' is provided in section 3.2.4, which discusses section 17 of the RMA. Cases that are relevant to the consideration of objectionable and offensive effects under the RMA are Zdrahal, [ Zdrahal v Wellington City Council [1995] 1 NZLR 700; (1994) 2 HRNZ 196; [1995] NZRMA 289 (HC).] De Coek [ De Coek v Central Otago District Council[1995] NZRMA 324.] and Minhinnick. [ Watercare Services Ltd v Minhinnick[1998] 1 NZLR 294; (1997) 3 ELRNZ 511; [1998] NZRMA 113 (CA).] In these cases it was noted that whether something was noxious, dangerous, offensive or objectionable had to be linked to whether it was of such an extent that it has or is likely to have an adverse effect on the environment.

In Zdrahal,the test for what may be offensive or objectionable was discussed. It was not considered sufficient that:

• a neighbour or other person within the relevant environment considers the activity or matter to be offensive and objectionable; or
• that the Tribunal itself might think the matter was objectionable.

The then Planning Tribunal considered that the person must not be hypersensitive but that their views must be "reflective of the opinions of a significant proportion of the public". The Tribunal found that in order to decide on such a matter, it must transpose itself into the ordinary person representative of the community at large. This means that for an odour to be considered objectionable or offensive in the eyes of the Court, information on the effects of the odour must be gathered which demonstrates that the test of the ordinary reasonable person can be met. This generally means that a history of complaint information, council officer investigations and evidence from affected parties is needed for such a case.

3.3.2 Effects

'Effect' is defined in section 3 of the RMA as including:

a) any positive or adverse effect; and

b) any temporary or permanent effects; and

c) any past, present, or future effect; and

d) any cumulative effect which arises over time or in combination with other effects -

regardless of the scale, intensity, duration or frequency of the effect, and also includes -

e) any potential effect of high probability; and

f) any potential effect of low probability which has a high potential impact.

Two cases have considered the meaning of 'effect' in relation to odour emissions, in particular, temporary odour effects of low probability (acute effects). Different outcomes have resulted depending on the circumstances. In Te Aroha Air Quality Protection Appeal Group v Waikato RC [(No 2) (1993) 2 NZRMA 574 (PT).] the risk of objectionable odour from a proposed rendering plant, although of low probability, was considered unacceptable given the sensitivity (zoning) of the receiving environment and the non-complying status of the proposed activity in terms of the district plan. In RC Vosper & Sons Ltd v New Plymouth DC [[1994] NZRMA 324 (PT).] the risk of an odour from a proposed cremator was not considered to be one of "high potential impact". This was because although the odour could be considered offensive by association with the activity, it would be temporary and not liable to affect a wide area.

Current case law does not include the use of the terms 'chronic' and 'acute' that are introduced in this guide. However, their meanings are reasonably consistent with the definition of 'effect' given above in subsections (e) and (f) respectively.

3.3.3 Internalisation

The principle of 'internalisation' is that those who create adverse effects must confine them within their own sites rather than force society to bear the burden of dealing with them. This principle has its origins in common law associated with property rights and nuisances. Two cases under the RMA that relate to internalisation are Hill v Matamata Piako DC & Waikato RC [(EnvC) A065/99.] and Winstone Aggregates Ltd v Papakura DC. [(EnvC) A096/98.] In these cases the Court found that objectionable effects could not be contained within the site and so deferred the applications for resource consent until it could be demonstrated that odour effects could be controlled via procedures documented in a management plan.

In Hill v Matamata Piako DC & Waikato RC the Court stated:

We reiterate again in this decision that we are of the view that adverse effects such as objectionable odour emissions should be confined on site. People living and working in rural neighbouring properties adjacent to sites where intensive farming such as broiler chicken rearing is carried out should not be subjected to objectionable and nauseating odours. It is incumbent upon the industry as a whole and upon individual farmers to so arrange their affairs in the way of siting, management, technology and feed formulations to ensure that objectionable odours are confined on site. This may well involve extra cost to the industry generally and to particular farmers. As a general principle we are of the view that such cost should be borne by the industry in the event that the siting of operations is such that there is potential to cause adverse effects.

The Court accepted that a condition requiring a buffer zone to disperse odours and prevent adverse effects may be reasonable in certain circumstances, but only where all reasonable measures have first been implemented to internalise the adverse effects.

3.3.4 Reverse sensitivity

The term 'reverse sensitivity' refers to the constraints that an activity may impose upon another less-sensitive activity. Auckland RC v Auckland CC [(EnvC) A010/97.] defines reverse sensitivity and confirms that it is appropriate in some circumstances to make provisions addressing reverse sensitivity in district plans.

In McMillan v Waimakariri DC [(EnvC) C87/98.] a zone change to allow for a subdivision adjacent to two pig farms was declined on the basis that the change did not meet the purpose of the RMA. This was because the plan change would not be an efficient use of land in the area and the pig farms would challenge the amenity values of the subdivision. In this case it was considered that there was adequate land available in the district for rural-residential development.

All activities are still under an obligation to avoid, remedy or mitigate adverse effects and contain adverse effects within their own sites; the overriding duty in section 17 still applies. Managing Rural Amenity Conflicts (Ministry for the Environment, 2001b) provides more detail and case law on internalisation and reverse sensitivity.

3.4 Resource consent conditions

Conditions in resource consents relating to odour must be clear, reasonable and enforceable. But because odour effects are often highly subjective there are special considerations when formulating consent conditions for odour discharges. In particular, a condition relating to 'no objectionable or offensive odour' will often be supported by other types of conditions. Examples of the types of resource consent conditions that may be applicable are:

• odour emission limits (e.g. measured from a stack or over an area)
• control equipment performance requirements (e.g. odour concentration)
• control equipment requirements (e.g. specifying biofilter depth, or incinerator temperature and retention time)
• operating and management requirements.

Design specifications are sometimes used in consent conditions to ensure that control equipment meets a minimum acceptable standard. The degree of specification needed in the consent depends in part on the track record of the consent holder in applying the best practicable option (section 3.4.2), and the amount of information provided in the application. There needs to be a balance in the conditions between flexibility for the consent holder to use any technology to achieve odour reductions, and certainty for the regional council and neighbours that appropriate technology will be utilised.

Some legal principles for formulating conditions relating to odour effects are discussed below. Guidance on consent duration for odorous activities is not provided. For further information on drafting consent conditions, refer to Effective and Enforceable Consent Conditions (Ministry for the Environment, 2001a) and Appendix 2 of the Technical Report (Ministry for the Environment, 2002c), or contact your local council.

3.4.1 Objectionable and offensive odour

Based on the discussion in this report, the recommended consent condition for the environmental effect of an odour is that it should be of the general form:

There shall be no objectionable or offensive odour to the extent that it causes an adverse effect at or beyond the boundary of the site.

It is usually insufficient for an odour to simply be detected at or beyond the boundary of a site. As discussed in section 3.3.1, the odour must be sufficient to create an adverse effect and the odour must be objectionable or offensive in the opinion of an 'ordinary reasonable person'. Further, for a breach of the condition to occur it would generally not be sufficient for one person or one council officer to find an odour objectionable in a one-off situation unless it can be demonstrated that an adverse effect has occurred in that instance. Whether there is a breach is always dependent on all of the FIDOL factors. All the recommended assessment methods are to assist in determining whether the above consent condition or minimum standard can be, or is being, complied with for an individual discharge source. Sufficient proof is required before enforcement action can be taken in relation to this condition.

3.4.2 Applying the best practicable option

Section 108(1)(e) of the RMA makes provision to include a condition requiring the consent holder to adopt the best practicable option to control any adverse effects caused by a discharge. The best practicable option (BPO) in relation to the discharge of a contaminant or an emission of noise is defined in section 2 of the RMA as the best method for preventing or minimising the adverse effects on the environment, having regard to:

(a) the nature of the discharge or emission and the sensitivity of the receiving environment to adverse effects; and

(b) the financial implications, and the effects on the environment, of that option when compared with other options; and

(c) the current state of technical knowledge and likelihood that the option can be successfully applied.

The Medical Officer of Health v Canterbury Regional Council and Ravensdown Fertiliser Co-operative Limited [(PT) W109/94.] dealt with the BPO under section 108. The then Planning Tribunal stated that in its view the key word was 'practicable':

Practical effect is given to those requirements [the provisions of section 108] by ensuring that the contaminants discharged by the applicant are at a level which on the best scientific and technical information available constitute the best practicable option of minimising adverse effects on the environment.

In that case, odour from the factory was said to be capable of adversely affecting the amenity values of the area. But the Planning Tribunal noted that there was nothing known to science and technology at the time of the case that meant odours from the factory could be completely eliminated. The Tribunal was satisfied that all that was practicable at the time was being done to minimise the adverse effects of the odour discharge on the environment. The Tribunal considered that its duty was to ensure that suitable conditions are imposed which require the applicant to adopt the BPO for preventing or minimising odour into the surrounding community. Therefore, the BPO does not necessarily mean the complete elimination of adverse environmental effects. However, if adverse effects are significant despite applying the BPO then it brings into question whether the consent should be granted.

The BPO is restricted under section 108(8) of the RMA so that the inclusion of a condition requiring the BPO must be the most efficient and effective means of preventing or minimising any actual or likely adverse effects on the environment to an "acceptable" odour effect level. When applying the test of efficiency and effectiveness, the regulatory authority needs to consider not just the efficiency from the applicant's viewpoint but also from the council's and the community's perspective.

In Australasian Peat Limited v Southland Regional Council [(PT) C44/96.] the Planning Tribunal required certainty in relation to a condition requiring the best practicable option for the control of dust. The Tribunal stated that the best practicable option must be specified, i.e. that the measures to control dust must be included in the consent. Therefore BPO conditions must include specific details about the equipment required and performance standards that should be monitored to ensure the ongoing effectiveness of the BPO.

Further information on odour control and best practice guidance is provided in section 5.2.

3.4.3 Management plans

There are two different approaches to management plans:

1. the management plan may be approved by the local authority (or the Court - in the case of an appeal) and written into the conditions of the resource consent; or
2. the resource consent requires the consent holder to prepare and lodge a management plan with the local authority after the consent is granted.

Relevant cases where the Court required the management plan to be approved and incorporated into consent conditions are Hill v Matamata Piako DC [(EnvC) A065/99.] and Purnell v Waikato RC. [(EnvC) A085/96.] In Hill the Court held that that the proponent of a chicken broiler operation must satisfy the Court that a proper management system would be put in place to sufficiently mitigate the effects of odour before a consent could be granted.

In Wood v West Coast RC [(EnvC) C127/99.] and Walker v Manukau CC [(EnvC) C213/99.] the Court has taken the approach of allowing a consent holder to lodge a management plan from time to time with the local authority. The Court agreed, in the case of noise, that:

... specific noise control limits can be laid down but the way in which these are to be complied with is for the consent holder who can be required to provide a management plan containing information about the method of compliance. However, because technology might change over time the consent holder should have the ability to change the management plan without having to go through the process of seeking a change to the conditions of consent.

In the case of Walker the Court held that consent conditions requiring a management plan to be approved by an officer are invalid, stating:

Either there should be a management plan prepared now, approved by this Court, and written into the conditions of the land use consent, or there should be no more than a requirement that the consent holder prepares and lodges a management plan from time to time with the respondent.

Where site management is critical to ensuring good odour performance, management-based controls should be identified at the time of the consent application. This can take the form of a management plan that, for complex activities, may need to be submitted as a draft for later approval. Specifying management techniques at the time of considering the consent provides a level of certainty that the odour effects condition can be achieved. More information on management plans can be found in sections 4.9 and 5.2.2.