Development of odour assessment criteria in New South Wales and application of the criteria for the assessment of a major public works project.
The introduction of the forthcoming Australian and New Zealand standard on odour measurement has led to the review of odour regulation in most Australian states. In New South Wales the regulator has drafted an odour impact assessment policy for point source emissions. The policy is based on the new odour measurement standard and defines regulatory dispersion modelling procedures. The New South Wales odour assessment policy was initially drafted on the basis of a literature review and has since been developed in consultation with various industry and government groups, including sewerage authorities. The policy, while still officially regarded as a draft, has already been used as the basis for the assessment of a number of sewerage projects that have been characterised by point source emissions. The application of modelling-based assessment procedures requires careful judgement concerning the selection of input data and close scrutiny on behalf of the assessor. This paper examines the assumptions underlying the development of the New South Wales draft odour assessment policy and draws important universal lessons from its application for the assessment of a major sewerage project. The introduction of peak to mean factors based on one second nose response times has been controversial and alternative procedures are proposed.