The presence of bacteria in the indoor air pose a serious problem from the point of view of health protection and environmental engineering. Precise determination of various groups of bacteria indoors is necessary for both to estimate the health hazard and to create standards for indoor air quality control.
This is especially important in such densely populated facilities like educational institutions. Results: In the present study, 252 samples of indoor air and air conditioners of 25 schools (Middle Schools) Public and Special, those were collected from east and centre of Riyadh in, Saudi Arabia, between October and November 2015. The most common bacterial isolates were, Gram negative bacteria (Pseudomonas stutzeri, Francisella tularensis and Ralstonia mannitolilytica ) of the total airborne bacteria.