Investigation of Building - Influenced Atmospheric Dispersion Using a Dual Source Technique

Dispersion of atmospheric contaminants in the vicinity of an isolated cubical model building was investigated in the field. A dual source/receptor technique was used in the experiments, which was proved to be very useful for the investigation of pollution dispersion. This experimental technique involved the simultaneous release of two different tracer gases from two different point sources, and the deployment of a FID (Flame Ionization Detector) co-located with a UVIC®(Ultra-Violet Ion Collector) detector. Both mean concentrations and concentration fluctuation statistics were examined. In this paper concentration fluctuation statistics are presented. The effect of the upwind source location on intermittency values and on the cumulative density function (cdf) is examined. The exact location of a source placed upwind of an obstacle has a very significant and complex effect on both mean concentrations and concentration fluctuations. As the lateral or vertical displacement between the two sources is increased, cross-correlation values between data taken simultaneously by two co-located detectors decrease rapidly.