Effect of electrical charges on potential of fibers for transport of microbial particles in dry and humid air

The quantitative assessment of electrically charged culturable microbial particles revealed that fibers were able to transport in the air up to 100 bacterial vegetative cells/spores or fungal conidia per 1 fiber. The most effective in this case were animal (dog and horse) and plant (cotton) fibers. Both tested man-made fibers were significantly less efficient than natural ones (p < 0.05). The study also showed that fraction of culturable microorganisms generated into the air and subsequently transported on fibers may reach 50% of total bioaerosol particles. In the environment of low air humidity (RH < 30%), the percentage of culturable microorganisms was always higher than those in high (RH > 60%) humidity conditions (p < 0.05). Moreover, the highest percentage of culturable microorganisms was always noted when the particles (bacterial vegetative cells or spores as well as fungal conidia) were electrically neutralized (0 V). Each time when microbial particles were electrically charged (± 500-4500 V), such process decreased the percentage of culturable bacteria and fungi (p < 0.05). This phenomenon can be explained by a disruptive influence of electrical conduction on viable microorganisms in the environment in which water is relatively easily available.