Environmental Study in Subway Metro Stations in Cairo, Egypt: Abdel Hameed A. Awad, Air Pollution Department, National Research Centre—Airborne viable and non‐viable measurements were carried out in two different metro stations, one located in a tunnel and the other on the surface. The concentrations of airborne total viable bacteria (incubated at 37°C and 22°C), staphylococci, suspended dust and oxidants (ozone) were higher in the air of the tunnel station than those recorded at the surface station. In contrast, spore forming bacteria, Candida spp, fungi and actinomycetes were found at slightly higher levels in the surface station than in the tunnel station. A statistically significant difference (p<0.01) was found between the levels of suspended dust at both stations. Cladosporium, Penicillium and Aspergillus species were the dominant fungi isolates. Fusarium, Aspergillus and Penicillium are the most common fungi that produce toxins. Under certain circumstances (host susceptibility, infective dose and aerodynamic diameter) some of the airborne microorganisms e.g. actinomycetes and Aspergillus species and staphylococci may cause health problems in exposed persons based on toxic or allergic reactions.

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 µm. Particulate sulfate (SO₄ ²⁻), nitrate (NO₃ ⁻), chloride (Cl⁻), ammonium (NH₄ ⁺) and lead components of suspended dust averaged 2960, 28, 1350, 100 and 13.3 µg m⁻³, respectively. Viable fungi associated with suspended dust and that in air averaged 1.11 × 10⁶ 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 µm whereas Aspergillus, Penicillium and Verticillium have dae <5 µm 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.