Microbiological air quality in office buildings equipped with dventilation systems

Abstract

Proper hygienic conditions in office buildings are of a high importance for both health and well-being of the employees. The aim of this study was the direct comparison of different ventilation systems on microbiological environments in 15 office buildings. The results showed that both bacterial and fungal concentrations in the naturally ventilated office buildings were between 70 and 1600 cfu/m , while in the offices equipped with air-conditioning and mechanical ventilation systems, concentrations were lower, that is, between 10 and 530 cfu/m and 20 and 410 cfu/m , respectively. The size distribution analysis revealed that microorganisms were present in the air mainly as single cells (1.1-3.3 μm) and large aggregates (4.7->7 μm). If deposited in the human respiratory tract, they may be responsible for nose and eyes irritations, asthmatic reactions, and allergic inflammations. The most prevalent bacterial species indoors were Gram-positive cocci (mainly from Staphylococcus and Micrococcus/Kocuria genera) and endospore-forming Gram-positive rods (from Bacillus genus). Among the most common fungal species were those from genera Penicillium, Aspergillus, and Cladosporium. Effectively working and regularly maintained mechanical ventilation or air-conditioning systems ensure a better hygienic quality in the office buildings than natural/gravitational ventilation.

Bioburden Assessment by Passive Methods on a Clinical Pathology Service in One Central Hospital from Lisbon: What Can it Tell Us Regarding Patients and Staff Exposure?

“…Thus, an intervention aiming at air cleaning with ultraviolet germicidal irradiation, such as ultraviolet with wavelength between 200 nm and 280 nm (UVC) [30] should be ensured, covering both fungi and bacteria elimination in the Clinical Pathology Service. Additionally, HVAC systems (including ventilation grids) should be maintained and properly preserved, since their efficacy in reducing microbial contamination has already been demonstrated [52,53].…”

Application of Airborne Microorganism Indexes in Offices, Gyms, and Libraries

“…In buildings equipped with centralized ventilation systems there is a reduction of microbial contamination compared to the outside when air filtration and treatment systems are maintained in appropriate conditions [22]. The air inside buildings may be contaminated by the growth of microorganisms on floors, walls, aeraulic plants or because of inadequate air changes [23]. The ventilation systems can have very different structural characteristics, ranging from the simple aspiration of exhaust air to integrated heating, cooling, and humidification.…”

Bacterial community analysis of floor dust and HEPA filters in air purifiers used in office rooms in ILAS, Beijing

“…Moreover, limited studies were carried out on the microbial community in HEPA filter in an air purifier, while most focused on microbes in HVAC filter 24,[27][28][29][30][31] . Knowledge of microbes in HEPA filter in office was also lacked, except the concentration and the size distribution of microbes 32 . Settled dust (SD), which well reflects the microbial composition in indoor air [33][34][35] , was commonly used to explore the indoor microbial community 36 .…”