STABLE TRACER AEROSOL DEPOSITION MEASUREMENTS IN A TEST CHAMBER

In order to provide data for evaluating the exposure of domestic building occupants to particulate pollutants from a variety of sources it is necessary to to carry out aerosol deposition experiments in real house environments. To complement such studies in real houses, in which many influences on aerosol deposition exist simultaneously, it is desirable to carry out aerosol deposition experiments in test chambers under controlled conditions. An aerosol test chamber, with the dimensions of a small room, is described. The chamber is fitted with air sampling ports so that aerosol deposition velocities can be inferred by monitoring tracer aerosol concentration decay. The use of neutron-activatable aerosol facilitates simultaneous surface sampling. This is not possible with conventional light-scattering aerosol detection techniques and thus provides valuable information on mass transport limited deposition. Aerosol deposition experiments have been carried out, under turbulent conditions using monodisperse neutron-activatable particles of four sizes. Results are compared with the theory of Corner and Pendlebury (1951, Proc. Phys. Soc. B64, 645-654). Surface sampling has been used to obtain additional information from average aerosol deposition velocities. The potential of the test chamber as a means of assessing the influence of internal building surface character upon aerosol deposition velocity is illustrated.