Effect of Carbon-Fiber Negative Air Ionization (NAI) on Air Sampled in a Pediatric Hospital: Culturable Airborne Bacteria, Species Diversity, and Biofilm Formation

Bioaerosols in hospital air pose a threat of respiratory infections, particularly among immunocompromised patients. Abating their effects by diverse methods proposed for air purification remains an open topic. In particular, low environmental bioaerosol concentrations, alongside species diversity, make such studies more difficult. We designed environmental indoor air samplers aimed at: (i) direct collection and quantification of culturable airborne bacteria from a selected location and (ii) accurate evaluation of effects of negative air ions (NAIs) on airborne bacteria. We studied ion–bioaerosol interaction in three distinct pediatric hospital departments by collecting non-treated (NTAS) and ion-treated (ITAS) samples side by side. Air was sampled at 0.5 m/s for 90 min (68.7 m3), with airborne bacteria collected directly onto chromogenic media. NTASs were dominated by Micrococcus luteus (58.27%), Staphylococcus hominis (15.56%), and S. haemolyticus (10.37%). ITASs were dominated by M. luteus (38.73%), S. haemolyticus (20.42%), S. hominis (12.68%), and S. warneri (11.27%). Overall, bacterial counts were 1.37–6.13-fold higher in NTASs than in ITASs across isolated species, indicating a substantial reduction in culturable airborne bacteria following NAI treatment. These findings show the promise of carbon-fiber-based NAI technology as a complementary approach to improving hospital air quality and reducing airborne bacterial contamination.