The development of a method to measure the spatial and temporal heterogeneity of vapour clouds in the field

One of the main difficulties in assessing the downwind hazard from an atmospheric pollutant or an accidental release of a toxic chemical is a lack of information on the likely spatial and temporal heterogeneities in concentration which may occur. If field trials are to be conducted, an environmentally acceptable tracer coupled with a detector with both a quantitative and rapid response is required. Ethanol is suggested as a tracer and the development and characterization of a detector is discussed.