Investigation of microbial quantity of indoor and outdoor air of selected daycare centers in different districts and seasons of Ahvaz

Aim and Air pollution is considered as one of the major causes of environmental health problems. Young children are more susceptible than adults due to age and higher sensitivity health hazards. The aim of study was to investigation indoor/outdoor, regional and seasonal variations of bio-aerosol emission of selected child daycare centers (sites) in Ahvaz city.
bio-aerosol samplings were performed bimonthly at indoor and outdoor of six sites at different region (industrial, residential, traffic) in a period of 8/12/2015 to 24/5/2016 and three seasons (autumn, winter and spring) in Ahvaz city. Air samplings were conducted by quick take. The flow rate and height were 28.3 lit/min and 0.8-1m above ground level respectively. Collected samples were immediately transferred in the cool-box to laboratory for further experiments. Tryptic soy agar (TSA) was used as nutrient media for the bacterial growth. After incubation, colonies on each plate were counted and the concentrations were calculated as colony forming units per cubic meter of air (CFU/m3). Genera identification of cultured airborne bacteria was conducted by examination of gram-stained smears and standard biochemical tests. It should be noted that due to the high number of isolates, a number of different colonies were selected based on the results of microscopic examination and also characteristics such as colony size, colony appearance and possible pigment from each plate.During sampling, indoor and outdoor temperature and relative humidity were measured.
The results shows that I/O rate of microbial populations at indoor was more than that of the outdoor. The most common bacterial groups found in outdoor and indoor air of the all sites were Gram-positive bacilli and cocci respectively. The highest and lowest concentrations of bacteria were observed in February and November respectively. The dominant bacterial genera were Staphylococcus spp. and Bacillus spp.
We can conclude that the highest and lowest mean concentrations of bacteria were observed at sites located in high traffic, crowded areas and residential and low traffic region respectively. There is no significant relationship between concentration of bacteria and temperature in the sampling sites.