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1 Introduction

1.1 Purpose of the Good Practice Guide

The purpose of this guide is to provide good practice protocols for assessing discharges to air from land transport in New Zealand. The information will enable transport and policy planners to determine whether a project is likely to have significant air quality impacts.

The guide only considers the effects of emissions to air from land transport, and principally those from petrol and diesel on-road vehicles. Shipping and aviation transport are not included. Projects involving maintenance works and/or minor safety upgrades are not likely to have significant air quality impacts and would not require assessment. Finally, the guide does not include guidance for assessing and controlling dust during the construction phase of relevant projects. Dust emissions are addressed by the Good Practice Guide for Assessing and Managing the Environmental Effects of Dust Emissions (Ministry for the Environment, 2001a).

For projects that are likely to have significant air quality impacts, a detailed assessment - including traffic modelling, vehicle emissions estimation and dispersion modelling - may be required. This type of assessment is complex and requires a multidisciplinary approach. The guide provides recommended protocols for these more detailed air quality impact assessments, but is not a substitute for expert input.

This guide is one of a series of good practice guides developed by the Ministry for the Environment. The series includes the:

  • Good Practice Guide for Assessing Discharges to Air from Land Transport (the subject of this guidance document)

  • Good Practice Guide for Assessing Discharges to Air from Industry (Ministry for the Environment, 2008)

  • Good Practice Guide for Atmospheric Dispersion Modelling (Ministry for the Environment, 2004).

There is a strong relationship between the guides. For example, if an assessment requires a quantitative estimation of pollutant concentrations from industry, this guide will refer you to the Good Practice Guide for Atmospheric Dispersion Modelling.

The Good Practice Guide for Assessing Discharges to Air from Land Transport applies the framework provided in the Resource Management (National Environmental Standards Relating to Certain Air Pollutants, Dioxins, and Other Toxics) Regulations 2004 (including amendments 2005) and the Updated Users Guide (Ministry for the Environment, 2005), which covers the regulations themselves. The aim is that the Good Practice Guide series, taken together, will help provide for comprehensive and consistent management of air quality in New Zealand. The framework for these documents is shown in Figure 1.1.

This Good Practice Guide for land transport makes recommendations for which assessment approach to adopt, while recognising the wide range of potential users. This may include transport or planning professionals, technical experts, council staff, hearing commissioners, and others who may be affected by the air quality effects of transport projects. Although the focus is on providing consistent guidance, there is some flexibility if documented and well-justified alternative approaches are proposed.

More specifically, this guide:

  • outlines the legislative context for the assessment process, in particular the Resource Management Act (1991) (RMA) and the New Zealand Transport Strategy

  • provides guidance on appropriate levels of assessment, given the variety of types of development for which assessment will be required

  • provides guidance on characterising both the development and the receiving environment

  • identifies the air quality criteria by which impacts should be assessed

  • provides guidance on key considerations under the national environmental standards for air quality

  • provides guidance on the methods available for assessing the impacts of air quality on both human health and the wider environment.

The assessment of potential dust and odour impacts arising from industrial emissions is not covered in any detail in this guide because these are the subject of existing Ministry guidance (Ministry for the Environment, 2001a and 2003b).

Although the aim of the guide is to promote national consistency in approach, it should be noted that the guidelines have no legal standing.

Figure 1.1 outlines how the guidance framework fits within the legislative framework. Figures 1.2 and 1.3 show the wide range of relevant Ministry for the Environment air quality publications, and their areas of applicability.

Figure 1.1: Legal and guidance framework for assessing discharges to air

Figure 1.2: New Zealand air quality guidance documents

Figure 1.3: Application of air quality guidance documents

1.2 Target audience

This document is aimed at practitioners making assessments of the effects of discharges to air from land transport projects, including consultants, council officers, scientists and reviewers. It is a detailed technical document, and as such it is not aimed at non-specialists such as the general public, lawyers, planners, hearing commissioners, or specialists in areas other than air. Although some sections may be useful to this latter group, the document has not been prepared with this audience in mind.

As noted above, it is designed to provide assistance, advice and sources of information with the aim of making the assessment process more streamlined and more consistent around the country. It is not binding, and in some cases the level of detail required will go beyond what has been covered here.