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Good Practice Guide on Assessing Discharges to Air from Industry

Foreword by the Ministry

Acknowledgements

1 Introduction

2 Legislative Context

3 Assessing Discharges to Air from Industry

4 The Assessment Process

5 Air Quality Criteria

6 Tier 1 Preliminary Assessment

7 Tier 2 Screening Assessment Process

8 Tier 3 Full Assessment Process

References

Appendix 1: Assessment Checklist

6 Tier 1 Preliminary Assessment

The tier 1 assessment is a qualitative assessment. The objectives are to compile background information, identify key issues, and determine the appropriate level of assessment. It is recommended that a tier 1 preliminary assessment be undertaken before the first pre-application meeting with the consent authority. The checklist in Appendix 1 may help in undertaking a tier 1 assessment.

The tier 1 assessment should consider the receiving environment and the nature and scale of the proposal, focusing on the:

• scale of the development
• nature of the pollutants released to air
• adoption of pollution prevention measures
• alternatives
• complaints/compliance record
• existing air quality including any airshed designation under the Standards
• physical geography of the receiving environment
• sensitivity of the receiving environment
• type of consent required
• any relevant objectives, policies or rules in the regional or district plan.

These factors are discussed further below. The level of detail required will vary depending on the proposal.

6.1 Proposals that do not require further assessment

It is likely that a tier 1 assessment will be all that is required for a permitted activity, or a controlled activity in an appropriately zoned area with no highly sensitive receptors located nearby. Discharges to air from these activities are likely to be minimal, and easily controlled by process design and standard operating practices. Adequate dispersion of air emissions should be achievable via appropriately designed discharge points. The potential for off-site human health, environmental or amenity effects would be low.

An assessment for this type of activity should include:

• any information that may be required by the relevant regional plan, including evidence that the activity is permitted or controlled
• the site location and contact details
• a process and site description, including quantities of raw materials and fuels to be used
• a description of emissions to air
• a description of emission controls and mitigation measures
• a description of the receiving environment, including air quality, topography and meteorology
• a qualitative description of the potential effects, taking into account the emissions and the receiving environment
• a summary of any complaints relating to discharges to air from the site.

6.2 Information required for a tier 1 assessment

The scale of the development

The scale of a development may be thought of in terms of throughput of raw materials or output of product relative to similar developments. The assessment should therefore include a description of the activity, including process throughputs and quantities of raw materials to be stored and handled. Typically, the scale of the development determines whether or not consent is needed. Clearly, it is more likely that larger-scale complex industry will require a higher level of assessment than smaller-scale activities.

The pollutants released to air

The assessment should include a description of the type and likely quantities of air discharges. This will influence the level of assessment required.

The type of consent required

The type of consent sought (ie, controlled, permitted, etc) will influence the level of assessment required. The preliminary assessment should include adequate information to demonstrate that the activity meets any requirements of the relevant regional plan for the type of consent required. The preliminary assessment should also consider whether the proposal may require other resource consents.

Pollution prevention measures

The assessment should review the existence and effectiveness of any pollution prevention measures, and whether the measures in place (or proposed) are consistent with best practice for the type of industry being considered. Pollution prevention measures may include:

• cleaner production technologies − where waste reduction is a focus of industrial process design and operation so that more benign and fewer raw materials are used, less energy is consumed, and fewer waste materials are released to air, land or water, etc.
• pollution control equipment (eg, the use of flue gas desulphurisation equipment with a conventional coal- or oil-fired power plant)
• the use of appropriately sized stacks to ensure adequate dispersion of emissions to air before a pollutant plume reaches potentially affected receptors
• the use of management or operational controls, such as process or emissions monitoring or management plans
• the use of buffer zones to separate receptors from industrial emission sources
• the provision of offsets.

The best local guidance on what constitutes best practice in terms of emission levels is set out in the NSW Department of Environment and Conservation (2002) Protection of Environmental Operations (Clean Air) Regulations. This regulation was amended in 2005 to incorporate emission concentration standards for new plant that reflect contemporary best practice control technology.

Secondary guidance on clean technologies and abatement equipment available to a wide range of industrial sectors is available from the website of the European Integrated Pollution Prevention and Control Bureau (http://eippcb.jrc.es/). This provides reference documents on the best available techniques under the EU Integrated Pollution Prevention and Control Directive.

Offsets are another potential form of mitigation, whereby emissions from an activity are 'offset' by emission reductions elsewhere in an airshed (see section 5.1.1 for further explanation of offsets). The Updated Users Guide (Ministry for the Environment, 2005b) expands on this form of mitigation.

Pollution prevention measures act to prevent and minimise the potential impacts of industrial emissions to air. A well-controlled industrial development, from the perspective of emissions to air, would be expected to require a lower level of assessment and have a greater chance of proceeding than one that is poorly controlled.

Alternatives

The tier 1 assessment should consider alternatives, including:

• alternative locations that may be less sensitive
• alternative methods of undertaking the activity (eg, cleaner production)
• alternative methods of pollution control that may reduce emissions
• whether the discharge could be to another receiving environment (eg, into water rather than air).

The complaints/compliance record

For an existing industry applying for consent renewal or expanding in scale, the complaints history will be a relevant factor.

When it comes to air quality, the most frequent complaints are about dust and odour. The Ministry for the Environment provides separate guidance for assessing dust and odour impacts, which should be followed if these have the potential to persist or occur (Ministry for the Environment, 2001a and 2003, respectively). Clearly, where a complaints record indicates there are existing community concerns regarding an air quality issue relevant to an application, a higher level of assessment would be expected.

Similarly, where an existing industrial development is seeking consent for expansion or alteration, the consent condition compliance record should be examined (eg, compliance with stack emission limits). Where compliance has been poor, the engineering design should be improved.

Overall, the level of assessment expected is likely to be higher for an industry with a poor compliance record.

Airshed designation under the National Environmental Standards for Air Quality

At the time of publication, 42 areas throughout New Zealand have been gazetted as 'airsheds' under the provisions of the Standards. These airsheds are subject to strict controls on the granting of resource consents for discharges to air, particularly PM₁₀, and most councils are formulating new policies and plans to manage air discharges. It is likely that any industrial development within these airshed areas that shows any increase in PM₁₀ emissions will require a tier 3 assessment. Airshed designations are discussed in more detail in the Updated Users' Guide (Ministry for the Environment, 2005b).

The existing air quality

Existing air quality is an important consideration in any air quality assessment. The tier 1 preliminary assessment should determine what information is available (if any) on existing air quality, and how this compares to relevant air quality criteria.

The physical geography of the receiving environment

The physical geography of an area can affect the dispersion of pollutants, and is a particularly important consideration in dispersion modelling. The preliminary assessment should identify whether there are any significant topographical features that may affect dispersion.

Features such as coasts and mountainous terrain require more complex predictive modelling techniques than, for example, flat inland sites. These considerations are well covered in the Good Practice Guide for Atmospheric Dispersion Modelling (Ministry for the Environment, 2004a), which is a companion guide to this document. A qualitative consideration is briefly covered in section 5.

Regional and district plan requirements

The tier 1 assessment should include a review of the relevant regional and district plans to identify any objectives, policies or rules that should be considered.

The sensitivity of the receiving environment

Adverse effects on air quality can be exacerbated by the sensitivity of the receiving environment. An assessment of the sensitivity of the receiving environment requires an assessment of land use and the likely sensitivity of the local population to air emissions.

Table 6-1 provides a general classification of the sensitivity of various land uses to discharges of contaminants into air. Because land uses are the key criteria for classifying the sensitivity of the receiving environment, district plan zonings can have a large influence on an area's sensitivity. Higher-sensitivity land uses will require a higher level of assessment.

Table 6-1: Types of land use/location and the sensitivity of the receiving environment