Assessment of culturable airborne bacteria of indoor environments in classrooms, dormitories and dining hall at university: a case study in China

Abstract

University students' health may be adversely affected by exposure to indoor bacterial contaminants on their campuses. This study aims (1) to quantify culturable bacterial concentrations in three indoor environments at a university, (2) to investigate the influence of meteorological factors and gender, to assess the relationship between indoor and outdoor, and (3) to estimate the bacterial dose for university students in different indoor environments. Airborne bacteria samples were collected in 12 classrooms, in 12 living rooms and four bathrooms in two dormitory buildings, and in a dining hall. The results showed that the microenvironment in the female dormitory had the highest mean bacterial concentration (2847 CFU/m 3 ), whereas the lowest mean bacterial concentration was observed in classrooms (162 CFU/m 3 ). Indoor bacterial concentrations in male dormitories were significantly lower than in female dormitories probably because of crowding and increased ventilation. Outdoor weather conditions were associated with the indoor concentrations with regard to insufficient ventilation and varying outdoor concentration. The occupants' activity level was also more closely related to the indoor bacteria concentration in the residential setting. Students experienced about four times higher dose of airborne bacteria in the dormitories than in the classrooms and dining hall.

Seasonal variation and size distribution in the airborne indoor microbial concentration of residential houses in Delhi and its impact on health

“…Fungal aerosols started declining from July–August, which may be due to increased soil moisture and hence, decreased resuspension of fungi in these months (Fan et al, 2017 ; Rathnayake et al, 2017 ). A recent Chinese study performed by Li and co-workers reported interesting variation in the indoor microflora in male and female dormitories, according to data Female microenvironments have higher bacterial aerosols than females (Li et al, 2020 ).…”

Microbial, environmental and anthropogenic factors influencing the indoor microbiome of the built environment

“…Occupants serve as passive transport vectors [25] bringing microbes from outdoors or taking ones from indoors through food, fabric, or clothing [38,39], fuelwood chips [40], reservoir dust, and track‐in [41]. Indoor sources of microorganisms include surfaces, occupancy, and human activities, from where microbes can enter directly into the aerosol phase like the aerosolization of saliva, tap water, or through the shedding of bacterial‐colonized skin cells or indirectly through resuspension of settled dust [17,18,42] (Table 2). Human inhales 10–25 m 3 of air every day indicating indoor microbial diversity to be an important source for human exposure [17] and direct emission of bioaerosols from human sources is also known [18,19,45] as humans shed approximately 10 6 particles (>0.5‐µm diameter) per hour [17] and this actively shed human microbial content presents a source for seeding the built environment microbiome [18].…”

Bacteriological Examination of Used Towels from Female and Male Hostel of Federal University of Lafia

“…Women have been reported to have a significant diversity of microbes on their palms than men, this could be as a result of women activities like poor hygiene practices, Furthermore, poor hygiene practices may result in higher bacterial concentrations [14]. This finding contradicts the traditional belief that microbial contaminant levels from female hostel would be lower than in male hostel [15]. [16] have shown that the functional variation between male and female leads to the substantial difference of bacteria species in the hostel.…”

“…[16] have shown that the functional variation between male and female leads to the substantial difference of bacteria species in the hostel. According to [17] female towels had the highest bacteria load than male towels, this is a wellknown fact that the regular cleaning of the body with water done by female attract more bacterial and chances of infection. Therefore, the findings in this study concur with the report of [18] that females skin have varied microorganisms.…”