Evaluating the effects of purification technology and thermal environment on removal efficiency for airborne mold aerosols

Indoor microorganisms have impacted human health through aerosol transmission and inhalation exposure. However, the appropriate purification technologies and practical effectiveness are still underexplored. This study evaluated the performance of different purification technologies for bioaerosols and the effects of operating thermal environments. The Aspergillus niger, was used as an artificial pollutant, and a combined air sampling and culturable method was employed to determine the concentration of airborne aerosols. 35 permutations of experimental conditions with temperature of 13/18/23/28/33 °C and relative humidity of 25%/35%/45%/55%/65%/75%/85% were designed. Comparisons of filtration, photocatalysis, ozone, and plasma showed that plasma exhibited higher disinfection rates, approximately 82.1 ± 4.17%, which was 2.13 times that of natural decay. The relative humidity, rather than temperature, had a significant impact on plasma purification. As the relative humidity increased from 25% to 85% (increment of 10%), the disinfection rate first increased and then decreased, and the peak-value was found at 23 °C/55%. The work quantifies the effective purification technology for bioaerosols and reveals the influence of air temperature and humidity, which contributes to the development of testing standards when evaluating purification efficiency, and advances the practical applications to consider the indoor air pollutants and operational thermal environment conditions in buildings.