Virus removal by high-efficiency air (HEPA) filters and filtration capacity enhancement by nanotextiles: a pilot study

Portable household air purifiers are widely used devices designed to maintain a high-quality level of indoor air. Portable air purifiers equipped with the high-efficiency air (HEPA) filter served 100 h in a household space occupied by two adults without any symptoms of respiratory tract infection. The main objective of the study was to determine microbial contamination on the HEPA filter and to investigate if the selected nanotextile monolayer made of polyamide 6 (PA6) nanofibers can capture potential microorganisms when installed downstream of the HEPA filter as the final filtration medium. Samples were taken from the inlet and outlet surfaces. Samples from the nanotextile were collected in the same manner as from the HEPA filter. QIAStat DX® 1.0 Analyzer using the Respiratory SARS CoV-2 Panel multiplex PCR detection system was selected for microorganism detection. Adenovirus was detected on the inlet surface of the HEPA filter. The outlet surface of the filter contained no viruses included in the Respiratory SARS CoV-2 Panel portfolio. The nanotextile monolayer was replaced twice during the 100 h of operation, so three pieces were used and all contained coronavirus 229 E. Coronavirus 229 E was then detected in the nasopharynx of one of the members of the household as well. It may be assumed that the selected nanotextile is capable of capturing a virus of a small size.