Regional Air Quality

Information gathering

The first step in regional air quality planning is to obtain a clear understanding of the current (and historical) state of the environment, and the pressures that may affect air quality.

Information required to manage regional air quality issues

A comprehensive framework for managing ambient air quality will include all the elements shown in Table 2.

Table 2: Elements of an air quality management framework*



Ambient air quality standards

Based on health and environmental indicators. Provided by national environmental standards. Augmented by national ambient air quality guidelines and ambient targets specified in regional plans.

Monitoring networks

Must include both air quality and meteorology. Additional monitoring to that required for the purposes of the national environmental standards may be necessary.

Emission inventories

Emissions quantified by source and location.

Predictive models

Validated numerical prediction tools to calculate spatial, short and long-term impacts. Models are used to estimate projections for emissions inventories and the dispersion characteristics of an airshed to ultimately provide the comprehensive understanding of the airshed that is so necessary for determining action.

Regulatory instruments

Regulations, regional plans, by-laws, incentives, etc.


System to give information to public on air quality. Includes reporting requirements under national environmental standards.


Policies and measures to ensure standards are achieved and maintained (e.g. regional plans, airshed action plan).

* Source: 2011 Users Guide to NES for air quality

The ability to source suitable data to characterise the state of the environment will need to be considered against each of the elements of an air quality management framework. In order to effectively manage air quality in an airshed or region, it will be necessary to answer the following questions:

  • What are we trying to achieve? (national environmental standards for air quality, regional plan ambient air quality targets/goals, national ambient air quality guidelines).
  • What data are available on:
    • air quality (pollutant monitoring)
    • meteorology (meteorological monitoring)
    • topography
    • emissions (source, profile)
    • dispersion characteristics
    • population exposure (location, demographics, mortality and morbidity, health effects, costs)?
  • What are the limitations of the data?
  • What is the data showing us (current/historical trends)?
  • Are there appropriate quality control mechanisms in place (ie, is the data validated)?
  • What do we know that we don’t know? (uncertainties, error bars, upper and lower bounds on estimates)
  • Are there areas where good air quality is important, eg, national parks or pristine areas, communities with vulnerable populations? (This can help identify priorities).

The extent of data required will depend on whether relevant standards/guidelines are likely to be exceeded, as well as the size and complexity of the airshed or air quality management area. See the Good Practice Guide for Air Quality Monitoring and Data Management on the Ministry for the Environment's website for more information on establishing an air quality monitoring network.

Only once the current state of ambient air quality is adequately characterised and understood, is it possible to estimate the future state of air quality for a given area. This in turns requires air quality projections to determine whether relevant standards are likely to be met in future, and if not, what emissions mitigation and/or activity management measures will be required to meet them. Projections are also necessary to test the effectiveness of different policy options. Projections may be based on emissions inventories, predictive models and desktop analysis.

Information required to manage local air quality issues and amenity effects

Sources of information on localised air quality issues and amenity effects will include:

  • council staff observations
  • air quality monitoring data, including visibility monitoring
  • public complaints
  • public consultation and perceptions, including consultation with tangata whenua.

Developing ambient air quality targets

All regional councils have plans that include either air quality targets, objectives and/or goals. In any case, the national environmental standards for air quality provide baseline ambient air quality protection. The 2011 Users Guide to the national environmental standards for air quality provides a plain English outline of what the regulations mean, and suggestions on how they might be implemented. The Ministry for the Environment has also published guidance on compliance for councils with airsheds that exceed the PM10 standard.

For pollutants (and time averaging periods) not covered by the national environmental standards for air quality, the national ambient air quality guidelines provide the minimum requirements for outdoor air quality to protect human health and the environment. Section 3.3 of the guidelines provides a framework for using the air quality guidelines and establishing regional ambient air quality criteria. The guidelines also recommend when a regional council should take or consider taking action.

A number of regions have developed regional targets in accordance with this framework, which are more stringent than the air standards and/or the ambient air quality guidelines. These targets are intended to ensure air quality is maintained in areas where it does not breach the guidelines, and improved in areas where it does breach, or is close to breaching the guidelines. These regional targets take precedence over the air standards and guidelines.


Objectives should express the overall aim of how the council proposes to manage air quality and address both air quality management areas and local issues.

  • Where air quality is cleaner than the relevant standard, guideline or target, the objective should aim to maintain that quality, or even improve it.
  • Where air quality is degraded, the objective should include a commitment to its improvement.

Regional plans generally include objectives for managing ambient air quality as well as localised air quality effects eg, dust, odour and agrichemical spray drift. The Ministry for the Environment's good practice guides include background information and guidance for managing odour and dust.


Policies should describe how air quality objectives are to be achieved and guide decision-making. They should aim to:

  • achieve the emissions reductions required to meet the air standards, target or guideline values where they are breached
  • minimise adverse health effects
  • provide direction to territorial authorities on what matters should be managed through their district plans.

Policies could include:

  • restricting the installation of solid fuel burners for home heating
  • promoting measures to address motor vehicle exhaust emissions
  • avoiding adverse effects from agrichemical spray drift
  • applying ambient air quality targets
  • restricting outdoor burning. 


A regional plan may include rules to implement the policies, and can include rules to allocate the capacity of air to assimilate a discharge of a contaminant (s30(1)(fa)(iv)).

Rules for managing air quality could include:

  • Rules that prohibit activities (e.g. banning outdoor burning in an urban area), require resource consent (e.g. to deal with the effects of industrial discharges) or specify standards (e.g. to place restrictions on home heating).
  • A catch-all rule for industrial and trade premises that are not addressed elsewhere in the plan.
  • Rules requiring bufferzones to manage reverse sensitivity issues.
  • Rules requiring adoption of the best practicable option approach.
  • Rules to manage the potential cumulative effect resulting from discharges, which when taken individually are minor, but may have significant cumulative effects.

Effective rules should:

  • Be supported by clear policies, and where necessary, include either guidance or a definition to restrict interpretation. For example, if no objectionable odour or dust is included as a standard, the plan should identify the assessment criteria and the process used to determine if an air discharge is objectionable.
  • Be cross-referenced both within the plan and to other plans to avoid repetition or conflict. Rules about waste management, land use or water discharge can contain conditions related to effects on air quality, and may reduce the need for separate rules.
  • Set clear and definitive thresholds or levels where possible, such as that combustion processes over 10 MW are a discretionary activity.

Catch-all rule for industrial and trade premises and other discharges

Section 15 of the RMA distinguishes between discharges from industrial and trade premises and other discharges. Under s15(1), any discharge of a contaminant into air from any industrial or trade premises is allowed only if it is expressly authorised by a rule in a plan, a resource consent, or by regulations.

The opposite presumption applies to discharges of contaminants into air from any other source under s15(2): that is, unless there is a relevant rule in a plan, discharges of contaminants into air from sources other than industrial or trade premises can take place without a resource consent.

Therefore, without rules in a plan, discharges of contaminants into air from industrial or trade premises, no matter how minor, require resource consents, while possibly significant discharges from other sources do not.

A key function of regional plan rules is allowing minor discharges into air from industrial and trade premises that are unlikely to have any significant adverse effects, and to regulate any other discharges that may have significant adverse effects. A catch-all rule can be used for industrial and trade premises that are not addressed elsewhere in a plan.

Best practicable option

Under s2 of the RMA, the best practicable option (BPO) is defined as:

best practicable option, in relation to a discharge of a contaminant or an emission of noise, means the best method for preventing or minimising the adverse effects on the environment having regard, among other things, 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 the likelihood that the option can be successfully applied.

The best practicable option can be used:

  • where there is a lack of effects information
  • where a precautionary approach is justified, or
  • for issues such as odour where the effect is difficult to quantify and there are many contributing variables.

The best practicable option may only be used in a rule in circumstances as defined in s70(2) of the RMA, i.e. where the council is satisfied that having regard to –

(a) the nature of the discharge and the receiving environment; and

(b) other alternatives, including a rule requiring the observance of minimum standards of quality of the environment,—

the inclusion of that rule in the plan is the most efficient and effective means of preventing or minimising those adverse effects on the environment.

The best practicable option is often justified on an effects basis for air quality issues requiring certain technical approaches. Plan changes should be considered when the best practicable option is no longer necessary.

Methods (optional)

A regional plan may also include methods, other than rules, to implement policies.

Using methods other than rules may be appropriate for:

  • some industrial discharges, eg, best practice guidance, responding to complaints
  • outdoor burning, e.g. providing information and best practice guidance, use of bylaws.
  • home heating (in some regions), eg, providing information, use of economic instruments, responding to complaints.
  • transport sources, e.g. advocacy to improve use and maintenance of vehicles, and transport planning to lower emissions from vehicles and to reduce congestion.

Cross-boundary issues

The ability of a regional council to manage air quality can be affected by cross boundary issues, which can arise between:

  • districts within a region, e.g. reduced ambient air quality in one district affecting another
  • land and coast, e.g. emissions from ships
  • regions, e.g. inconsistent policies such as for burning vegetation or home heating controls
  • the region and the rest of New Zealand, e.g. consistency of ambient air monitoring data collection
  • countries, e.g. smoke from Australian bushfires.

The importance of identifying and managing cross-boundary issues has been highlighted through the national environmental standards for air quality, specifically the introduction of airsheds as the fundamental areas of air quality management. While airsheds are generally aligned to geophysical areas this is not always the case. For instance, the boundary between Nelson City Council and Tasman District Council is not based on geophysical criteria and air pollution can readily cross this boundary from one jurisdiction to the other.

Environmental results expected

A regional plan may state the environmental results expected to be achieved from the plan. These can include indicators or measures to assess progress towards achieving the plan's air quality objectives.

Indicators or measures could include, for example:

  • ambient particulate (PM10) concentrations do not exceed national ambient standard by 1 September 2016 (polluted airsheds) or by 1 September 2020 (heavily polluted airsheds)
  • a 50% reduction in the number of complaints relating to air quality by a certain date, and/or
  • ambient air quality remains within regional criteria.

Monitoring and review

Both monitoring and reviewing plan effectiveness is an important component of managing air quality effects, and is particularly important when working towards compliance with the air standards.

A council should develop and implement a clear regional air quality monitoring strategy to measure progress against air quality objectives and compliance with the air standards.

Ambient air quality monitoring is the primary means of assessing compliance with ambient air quality standards, guidelines and targets. The Ambient Air Quality Guidelines and the Good Practice Guide for Air Quality Monitoring and Data Management provide information on ambient air quality monitoring programme design.

Regional air quality monitoring strategy

An effective air quality monitoring strategy should:

  • monitor the state of the environment
  • monitor compliance with the national environmental standards for air quality in accordance with the requirements of Regulation 15
  • fill information gaps that have been discovered
  • test assumptions implied by the plan provisions
  • measure whether the plan is effective, by comparing actual results with the anticipated environmental results and measuring progress towards achieving the objectives
  • monitor consent compliance and complaints
  • monitor any delegations or transfer of powers

Further information on designing an effective ambient air quality monitoring programme is provided in the Good Practice Guide for Air Quality Monitoring and Data Management.

Mandatory ambient air quality monitoring

Regulation 15 of the national environmental standards for air quality requires councils to monitor air quality in airsheds where it is likely the standard will be breached. The monitoring must be carried out:

in that part of the airshed where –

(A) there are one or more people; and

(B) the standard is breached by the greatest margin or the standard is breached the most frequently, whichever is the most likely.

Monitoring must be carried out in accordance with the methods specified in Schedule 2 of the regulations.