This study aims to evaluate airborne environmental bacteria (environmental origin), mesophilic bacteria (human related bacteria) and fungi at governmental (GH) and private (PH) hospitals, in addition to assess sink drain biofilms and dust accumulated on air conditioning filters and floor surfaces to determine if they constitute potential sources of airborne microbial biodiversity. Samples were collected from intensive care unit (ICU), operating theatre (OT), admission department (AD) and outdoor for comparison. Airborne bacteria and fungi were collected using an Andersen two-stage impactor sampler which divides particles into fine (≤8 µm) and coarse (≥8 µm) size ranges. Airborne environmental bacteria, mesophilic bacteria and fungi concentrations, were respectively in the range of 0.0–2638; 0.0–1654.9 and 11.7–566.5 CFU/m3 indoors and 155–32436; 11.7–5554 and 35–664 CFU/m3 outdoors. Bacillus atrophaeus was commonly isolated in all locations. However, Alloiococcus otitis was only found at the GH and Bacillus licheniformis at the PH. Aspergillus and Penicillium were the common fungal types in the air state and dust. Dust was accumulated on air conditioning filters and floor surfaces and these would constitute important sources of airborne bacteria and fungi inside these hospitals.

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Airborne microbial contamination was collected from the main directions of the holy mosque (Al-Haram mosque), Makkah city, by using the gravitational method.Bacteria, fungi and actinomycete concentrations ranged between 1470 -21800 CFU/m 3 ; 44 -572 CFU/m 3 , and 0.0 -264 CFU/m 3 , respectively at all directions. Bacterial concentrations significantly differed between directions, and Gram positive bacteria constituted ~ 90-100% of the total bacterial isolates. Gammaproteo bacteria were the common Gram negative bacteria, and Aspergillus was the predominant fungal genera. Mesophilic bacteria negatively related (P< 0.05) with relative humidity. Human activities had more effective influence on the microbial concentrations than the meteorological factors.

Indoor and outdoor measurements of formaldehyde were conducted at seven flats located in residential areas in Greater Cairo, during spring and summer seasons 1999. The mean daytime formaldehyde concentrations in kitchens, bedrooms and living rooms were 89, 100 and 100 ppb, respectively, in the seven flats. Significant positive correlations were found between the concentrations of formaldehyde found in these three rooms. On the other hand, no significant differences were found between the mean formaldehyde concentrations in these three rooms. The maximum mean concentration of formaldehyde (147 ppb) was recorded in a new flat, while the minimum concentration (43 ppb) was observed in an old flat. The maximum hourly and daytime concentrations were 350 and 225 ppb, respectively. Air temperature, relative humidity and the age of the flat are factors affecting the emission and concentration of formaldehyde. The maximum indoor and outdoor formaldehyde concentrations were recorded during the summer season. During the spring, 38% of the samples indicated that the concentration of formaldehyde in the seven flats exceeded 0.1 ppm, the American Society of Heating, Refrigerating, and Air Conditioning Engineers' (ASHRAE) standard; in the summer, this figure increased to 53%.

A temporary renovation activity releases considerably high concentrations of particulate matter, viable and non-viable, into air. These pollutants are a potential contributor to unacceptable indoor air quality (IAQ). Particulate matter and its constituents lead, sulfate, nitrate, chloride, ammonium and fungi as well as fungal spores in air were evaluated in a building during renovation action. Suspended dust was recorded at a mean value of 6.1 mg m(-3) which exceeded the Egyptian limit values for indoor air (0.15 mg m(-3)) and occupational environments (5 mg m(-3)). The highest particle frequency (23%) of aerodynamic diameter (dae) was 1.7 microm. Particulate sulfate (SO(4)(2-)), nitrate (NO(3)(-)), chloride (Cl(-)), ammonium (NH(4)(+)) and lead components of suspended dust averaged 2960, 28, 1350, 100 and 13.3 microg m(-3), respectively. Viable fungi associated with suspended dust and that in air averaged 1.11 x 10(6) colony forming unit per gram (cfu g(-1)) and 92 colony forming unit per plate per hour (cfu p(-1) h(-1)), respectively. Cladosporium(33%), Aspergillus(25.6%), Alternaria(11.2%) and Penicillium(6.6%) were the most frequent fungal genera in air, whereas Aspergillus(56.8%), Penicillium(10.3%) and Eurotium(10.3%) were the most common fungal genera associated with suspended dust. The detection of Aureobasidium, Epicoccum, Exophiala, Paecilomyces, Scopulariopsis, Ulocladium and Trichoderma is an indication of moisture-damaged building materials. Alternaria, Aureobasidium, Cladosporium, Scopulariopsis and Nigrospora have dae > 5 microm whereas Aspergillus, Penicillium and Verticillium have dae < 5 microm which are suited to penetrate deeply into lungs. Particulate matter from the working area infiltrates the occupied zones if precautionary measures are inadequate. This may cause deterioration of IAQ, discomfort and acute health problems. Renovation should be carefully designed and managed, in order to minimize degradation of the indoor and outdoor air quality.