A knowledge of the air movement around a worker in a low-speed airflow is important in a number of areas: containment testing of fume cupboards; testing of personal dust samplers; testing of LEV effectiveness; and measurement of worker exposure. Measurements of velocity vectors around the upper torsos of manikins and a human in low-speed airflows have been made using a laser Doppler anemometer. Both heated and unheated manikins, as well as a 'breathing' manikin were used. The results show that quite distinctive flow patterns develop with heated and unheated bodies. Comparison of the flows around two- and three-dimensional manikins with that around a human shows that only a three-dimensional heated manikin gives good results. The unheated breathing manikin gave results which were unrepresentative of the real situation. A suitable manikin for use in sampling or testing in low-speed airflows would have a heated, rounded, three-dimensional body of reasonably human dimensions and would be non-breathing and clothed.

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Pesticide smoke generating products are widely used by amateurs and professionals but there is little published information available about their burn and deposition characteristics to enable the risks associated with using these devices to be assessed. This paper investigates their burn characteristics, deposition patterns, pesticide air concentrations and potential exposure to operators. Thirteen firings were carried out in different spaces with different ventilation conditions. Three types of devices were investigated: dicloran, permethrin and red dye. Pesticide air concentrations increased after firing, reaching a maximum determined by the room volume in approximately 10 min and decreasing exponentially as a result of ventilation and deposition. Ejected pesticide was present in the aerosol phase but there were only occasional traces of vapour. Settlement of pesticide was affected by surface orientation, height, sampling material and the pesticide-to-space volume ratio. The manufacturer's recommended treatment period for dicloran of 4 h followed by half an hour of ventilation may be insufficient to reduce pesticide to safe levels for re-entry under very calm conditions.

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