Influence of high-efficiency particulate air filtration on indoor air fungal contamination in a hospital in Mashhad, Iran

Poor hospital Indoor Air Quality (IAQ) may result in various occupational hazards, hospital-acquired infections, and sick hospital syndrome. Air-control measures are vital to reduce airborne biological particle dissemination in hospitals. This study aimed to evaluate the effectiveness of High-Efficiency Particulate Air (HEPA) filters in decreasing indoor fungal pollution in an organ transplantation hospital in Mashhad.

In this work, 96 specimens were collected from the air of three operating rooms and the Intensive Care Unit (ICU) ward. Sampling was performed using National Institute for Occupational Safety and Health (NIOSH-0800) instructions in two stages before and after using HEPA filters. Fungal density was reported based on the number of colonies per m3(CFU/m3).

According to the results before using HEPA filters, the colony frequency of Aspergillus was 50%, which was the highest among the detected fungi. Penicillium with a frequency of 23% was followed by Aspergillus. After using HEPA filters, the frequency of Aspergillus and Penicillium decreased by 40% and 6% to 10% and 17%, respectively. The mean concentrations of fungi in all three operating rooms and ICU before use and after using HEPA filters were 9.52 and 3.11 (CFU/m3), respectively indicating a reduction of about 67%, which is statistically significant (P≤0.005).

Hence, using these filters is recommended considering the good performance and high efficiency of HEPA filters in reducing fungal contamination and its consequences.