| Exposure to bioaerosols, especially to pathogenic or allergenic microorganisms, may cause a wide range of respiratory and other health disorders in occupational and general populations. Methods commonly used to monitor exposure to airborne microorganisms, such as impaction and impingement, are known to affect the viability of sensitive microorganisms, which, in turn, leads to underestimations of bioaerosol exposure levels. This research was undertaken to investigate the hypothesis that airborne biological particles can be efficiently collected by electrostatic means without being inactivated. In this method, the airborne particles are electrically charged and then deposited on a collection substrate by electrostatic forces.; This study has shown that collection of airborne microorganisms by electrostatic means is feasible, if electrical charging by corona discharge is avoided and the charge levels do not exceed certain positive or negative charge limits. The levels of electric charges on airborne microorganisms and their effect on microorganism viability and injury were studied using a newly designed and built experimental setup. In this setup, electric charges onto airborne microorganisms are imposed by means of induction charging. Microorganism fractions carrying electric charges of specific magnitude and polarity are extracted by an electrical mobility analyzer and collected by a microbial sampler.; It was found that electric charging by means of induction does not affect the bacterial viability. This study also found that microorganisms in the airborne state may carry more than 10,000 elementary electric charges, in which case their collection by electrostatics is possible without additional charging. It was determined, however, that very high positive electric charges inactivate sensitive bacteria, such as Pseudomonas fluorescens, while the viability of bacterial spores, such as Bacillus subtilis var. niger, carrying the same amount of electric charge, is not affected. It was also determined and that electric fields of up to 2,000 V/cm efficiently collect airborne microorganisms without affecting their viability.; The findings of this study have shown that collection of viable airborne microorganisms by electrostatic means has the potential for being an efficient and accurate collection method. Such a method may lead to more accurate exposure monitoring. |
