Biofiltration is a common technology to treat volatile organic compounds (VOCs), however, bioaerosols may be carried out by gas flow, suggesting a potential risk to human health. In this study, the emission characteristics of bioaerosol and suspended particles (mainly nonbiological particles) emitted from biofilters and their health risk with different gas velocities, gas temperatures and packing bed moisture contents were analyzed. Results showed that high gas velocity made microbes easily be brought away from the carriers. The maximum outlet bacterial aerosol concentration was 223 CFU m–3 at 50°C, while fungal aerosol concentration decreased as the temperature beyond 25°C. The peak bacteria concentration was 349 CFU m–3 with moisture content of 70% whereas the highest fungi concentration (nearly 267 CFU m–3) was observed at 40%. The bioaerosol concentration of different particle sizes also changes with experimental conditions. Moreover, fine particles emission is favored by large gas velocity, low temperature and high moisture content. However, the changes of coarse particles in concentration and size distribution are not obvious. Relationship between bioaerosol and suspend particles emission demonstrated that the biofilter is a bioaerosol emissions source but remove the nonbiological suspended particles due to its filtration. The health risk evaluation showed that adult males were under the highest risk of infections by bioaerosol emissions from biofilters through inhalation.