EFFICIENCY OF A LOW-ENERGY WETTED-SURFACE MULTI-ANNULUS DENUDER SAMPLER FOR VIABLE AND NONVIABLE AEROSOL COLLECTION

Capture efficiency of a wetted-surface low-energy sampler (LES) was ev aluated for polystyrene latex (PSL) microsphere aerosol and a Bacillus subtilis aerosol. The observed absolute capture efficiency for PSL mi crospheres was higher than predicted by theory for the particle sizes used (0.7, 1.6, and 3.0 mu m), suggesting hygroscopic particle growth via water uptake by residual detergent coatings. Bio-aerosol capture e fficiency was evaluated relative to the AGI-30 impinger using mature B . subtilis. The bioaerosol was quasi-monodisperse with MMAD approximat ely 1 mu m and GSD 1.2-1.3. Observed efficiencies for B. subtilis were substantially better for the LES than the AGI-30 at the lowest sampli ng flow rate used (5 L/min), but relatively poor at higher Row rates. Factors potentially influencing sampling efficiency were improved viab ility maintenance and adequate hygroscopic bioorganism growth in the L ES. These results demonstrate that low-energy bioaerosol sampling usin g a wetted-surface multi-annulus denuder may be more sensitive than AG I-30 impinger sampling for some organisms. (C) 1998 American Associati on for Aerosol Research.