Do full-scale gas-phase biofilters reduce or increase bioaerosol emissions?

Biofilters are widely utilized for treating odorous gases. Understanding the biosafety of biofilters in real-world applications necessitates a comprehensive investigation into their bioaerosol emission characteristics. In this study, bioaerosols captured from the inlet and outlet, along with packing material microbiome were investigated over a 12-month period from three full-scale biofilters. Their characteristics, size distribution, and sources were investigated and analyzed. Notably, over 96 % of the bioaerosols originated from the inlet air rather than from the packing materials. Full-scale biofilters not only reduced bacterial emissions by 5-17 % but also lowered the potential pathogenicity. Although biofilters effectively diminished bioaerosol emissions, there are still potential pathogenicity primarily originated from the inlet air. This study emphasizes the significance of considering upstream processes when evaluating the risks associated with bioaerosols in real-world applications.