The assessment of microbiological quality and some properties of indoor atmosphere in Port
Harcourt were carried out at seven different sites. Air samples were collected from these sites during the rainy and
dry seasons as well as day and night periods. Microbiological identification tests were performed on isolated
organisms while the environmental factors measured were air temperature, relative humidity and wind speed.
Results obtained indicated that all seven sites yielded microorganisms at different degrees with site 5 having the
highest microbial load and site 4 the lowest. The most conducive atmosphere for the growth and increase of
airborne indoor microorganism were temperature between 31°C and 32°C, dry, dusty atmosphere and an
overcrowded enclosure. The species of organisms isolated were Staphylococcus
species and Cladosporium
species. The study
revealed that no indoor atmosphere is completely free from microorganisms; rooms that carry above their original
design capacity for occupancy are prone to have a high load of microorganism and indoor microorganism survive
and multiply faster during the dry season compared to their growth in the rainy season.