PRELIMINARY ASSESSMENT OF A DEVICE FOR PASSIVE SAMPLING OF AIRBORNE PARTICULATE

The concept of passive sampling, widely used in personal gas and vapou r samplers and in radiation dosimeters, has been applied to aerosol sa mpling. A passive sampler has been developed, which consists of a perm anently charged polymer sheet (an electret) and a grid. The device col lects particles by electrostatic attraction, its sampling rate being i ndependent of the velocity of the ambient air outside the sampler surf ace provided that a critical velocity is exceeded. The primary factor governing the sampling rate is the electrical mobility of the aerosol particles, and so this parameter must be known if the sampler is to be used for absolute measurements. The device, which is light in weight, is likely to be acceptable to wearers and suitable for personal sampl ing, though it could be used in static sampling as well. Measurements made on laboratory-generated monodisperse aerosols, wood dust produced during sanding operations and the indoor ambient aerosol have demonst rated the potential of the technique.