the impact of visiting hours on indoor to outdoor ratio of fungi concentration at university hospitals in ahvaz, iran

The majority of diseases caused by air pollution, such as asthma and allergies, are caused by pathogenic bacteria, which are transmitted through bioaerosols. bacteria and fungi are the main sources of hospital infections causing the majority of diseases and cases of mortality. the aim of this study was to determine the ratio of indoor to outdoor fungi concentration, the effect of population density on fungi concentration, and the relationship between indoor and outdoor environments. in this study, 3 stations were assessed; the outdoor environment, general indoor environment, and intensive care units (icus) of a hospital affiliated to ahvaz university of medical sciences, iran. these stations were used for the sampling of airborne fungi from october to december 2010. the samples were collected over a period of 2 minutes in a flow rate of 28.3 l/minute using a quicktake 30 air sampling pump. the 3 dominant fungi genera in the sampling stations were aspergillus, penicillium, and cladosporium. the average of total fungi concentration before visiting hours was 365.8 cfu/m which was reduced to 578 cfu/m after visiting hours. the indoor to outdoor ratios in the icu and internal wards for fungi before visiting hours were 0.36 and 0.68, respectively. however, these ratios in the icu and internal wards for fungi after visiting hours were 0.78 and 0.99, respectively. following the visiting hours, the concentration of fungi available indoors was conspicuously higher (even in the wards in which no visitors were allowed (e.g., icus). hence, the amount of indoor fungi was affected by the concentration of outdoor fungi and the number of visitors.