Development and evaluation of a prototype system for collecting sub-hourlyambient aerosol for chemical analysis

Aerosol growth technology is used as a means of collecting ambient aerosol particles for subsequent chemical analyses. Condensational growth has previ ously been used in Condensation Nucleus Counters and in ultrafine particle concentrators at flow rates up to 110 L - min(-1). Here, air is sampled at a flow rate of 170 L - min(-1) and particles are grown by condensation of w ater vapor in a condenser maintained at 0.5 degreesC after saturation by di rect injection of steam. The resulting droplets are concentrated 13.6 fold using a twin-nozzle virtual impactor and collected in a liquid slurry with a real impactor in an all glass and plastic system. The prototype system's collection efficiency was tested with 0.1-3 mum monodisperse fluorescent po lystyrene latex particles. Particles initially <0.5 <mu>m are collected wit h an overall efficiency of 40%, which gradually increases to 68% for 3 mum particles. The system delivers an aerosol slurry at a rate of 0.2 mL min(-1 ), i.e., suitable for analysis by multielement Graphite-Furnace Atomic Abso rption Spectrometry, with system blanks adequate to permit quantitative ana lysis of Al, As, Cd, Cu, Fe, Mn, Pb, Sb, Se, and Zn in ambient suburban aer osol.