Grant: Discovery Grants Program - Individual

When a gas, which may be malodorous, flammable or toxic, is released into the atmospheric boundary-layer one would like to know the probable concentration values encountered at various locations and times. These concentration values are very difficult to predict or to measure.The environment is in a turbulent state and the very irregular values of concentration recorded in field (and also in laboratory) measurements commonly exhibit extreme excursions of concentration that are many times the nominal average level. The usual descriptor used for the quantification of concentration values is the probability density function however this is impractical in the environmental context. A new measure for quantifying concentration values has been proposed. The new measure-The Expected Mass Fraction Function-has significant advantages both in terms of the relative simplicity of the equations that govern its evolution and in the relatively small amount of measured concentration data required to compile this statistic. The proposal is to experimentally and theoretically investigate the behaviour of contaminant concentration values using the Expected Mass Fraction Function.