The use of dynamic olfactometry can provide the basis of an effective and comprehensive approach to establishing odour strength and odour intensity levels of complex odours. When coupled with odour dispersion modelling, dynamic olfactometry can provide a particularly useful basis for odour impact assessment. The use of dispersion modelling for odour impact assessment requires the acquisition of sound and reliable source data. In the past there have been difficulties with scientifically sound quantification of odours by olfactometry. Even today there are those who still believe the science of odour measurement is a “black art”. No doubt many that hold this opinion have had experience with early attempts at the sensory evaluation of odours using earlier olfactometry techniques. Fortunately in recent years the science of olfactometry has advanced greatly, resulting in improved accuracy and greater repeatability of results (Wenzel 1948; Hangartner et al. 1985). Much of the development of olfactometry has occurred in Europe where high population density has resulted in odour generated by intensive agricultural operations, which has severely impacted on residential amenity.
The design of instruments and materials of construction used in modern olfactometry, differs greatly from those used a decade or so ago. The use of calibrated olfactometers and screened panels has greatly improved the reliability of odour concentration measurements (Jiang 1996). Most importantly, olfactometric techniques have been standardised. The draft European standard prEN 17325 (CEN 1997) is a performance based standard and defines the unit of odour measurement in terms of a butanol reference material. The forthcoming Australia and New Zealand standard (DR 99306) is based on the European standard and applies identical performance-based criteria. Similarly, there have been developments in odour sampling techniques that have improved the science. It is now possible to transport odour samples to a laboratory without significantly affecting odour concentration or odour intensity during transport. Furthermore, the draft European olfactometry standard, referred to above, also specifies, at least in a general way, techniques for emission sampling.