Comparison of aerosol and bioaerosol collection on air filters

• Published in: Aerobiologia 2012-06, Vol.28 (2), p.185-193
• Main Authors: Miaskiewicz-Peska, Ewa, Lebkowska, Maria
• Format: Article
• Language: English
• Subjects: air; air filters; Allergology; Atmospheric Protection/Air Quality Control/Air Pollution; Bacillus subtilis; bacteria; bioaerosols; Earth and Environmental Science; Environment; Environmental Engineering/Biotechnology; Environmental Health; filtration; Kocuria varians; Micrococcus luteus; Original Paper; particle size; Plant Pathology; Pneumology/Respiratory System; potassium chloride; Pseudomonas putida
• ISSN: 0393-5965; 1573-3025
• DOI: 10.1007/s10453-011-9223-1

Air filters efficiency is usually determined by non-biological test aerosols, such as potassium chloride particles, Arizona dust or di-ethyl-hexyl-sebacate (DEHS) oily liquid. This research was undertaken to asses, if application of non-biological aerosols reflects air filters capacity to collect particles of biological origin. The collection efficiency for non-biological aerosol was tested with the PALAS set and ISO Fine Test Dust. Flow rate during the filtration process was 720 l/h, and particles size ranged 0.246–17.165 μm. The upstream and downstream concentration of the aerosol was measured with a laser particle counter PCS-2010. Tested bioaerosol contained 4 bacterial strains of different shape and size: Micrococcus luteus, Micrococcus varians, Pseudomonas putida and Bacillus subtilis. Number of the biological particles was estimated with a culture-based method. Results obtained with bioaerosol did not confirmed 100% filters efficiency noted for the mineral test dust of the same aerodynamic diameter. Maximum efficiency tested with bacterial cells was 99.8%. Additionally, cells reemission from filters into air was also studied. Bioaerosol contained 3 bacterial strains: Micrococcus varians, Pseudomonas putida and Bacillus subtilis. It was proved that the highest intensity of the reemission process was during the first 5 min. and reached maximum 0.63% of total number of bacteria retained in filters. Spherical cells adhered stronger to the filter fibres than cylindrical ones. It was concluded that non-biological aerosol containing particles of the same shape and surface characteristics (like DEHS spherical particles) can not give representative results for all particles present in the filtered air.