# Combating Pathogens Using Carbon-Fiber Ionizers (CFIs) for Air Purification: A Narrative Review
8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS]. (S.D.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (M.J.); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS] (A.N. ); [EMAIL_ADDRESS]. (S.D.) 8 Institute of Microbiology and Immunology, Faculty of Medicine, University of Belgrade, 11000 Belgrade, Serbia;  
1 [EMAIL_ADDRESS]. Among the physical means of disease prevention, there are several technologies aimed at reducing the infectious burden carried by pathogen-laden aerosols. The main goal of air purification technologies is to either influence the viability of microorganisms or simply eliminate microbes from the circulating air. Air ionization is known to enhance the natural deposition of particulate matter through electrostatic effects [2; 3]. It is assumed to be able, to some extent, to also inactivate or weaken microorganisms [4]. Small air ions for the purposes of air purification have to be generated artificially. Two types of artificially produced air ionization, which are mostly used in practice, are the dielectric barrier discharge (DBD) and the corona discharge at the metallic electrode tip. Both types of small air ion generation produce ozone as a byproduct, a sterilizing gas that is highly reactive and, in higher concentrations, harmful to living organisms. Recently, the use of carbon fiber corona discharge has become highly popular. Unlike the thin metal tip electrode, carbon fibers consist of entire bundles of extremely thin spikes, the fiber tips, allowing them to produce remarkably high concentrations of ions with negligible ozone production [5; 6]. As a result, the minimal voltage to produce carbon fiber-based ionization is below 5 kV, whereas about 7 kV is required when working with the metallic electrodes. Apart from the practical merit of later use of carbon fiber corona discharge ionizers, it is also highly important from an experimental point of view to use ozone-free ionization.