An investigation into the types and numbers of airborne microorganisms
was carried out in three varying types of residential houses in Al-Ai
n City, UAE, to establish future reference standards and to determine
if they have affected, and to what degree they may affect, human healt
h. Samples were collected using a microbial mechanical air sampler for
the enumeration of bacterial and fungal colony forming units (CFU). N
ine groups of bacteria and fungi either of human or environmental orig
in were detected. Environmental agents generally predominated while si
gnificantly higher counts were detected as the level of hygiene or sta
ndard of housing dropped. Significantly higher human associated microo
rganisms were detected in bedrooms while environmentally-related micro
organisms were more commonly found in living rooms. Only small numbers
of potential human pathogens were detected, Five genera of fungi, mai
nly members of the genus Aspergillus, were isolated from all houses ac
ross the board. Microbial occurrence and indoor air quality in the hig
h social strata houses were similar to that reported in clean hospital
environment rooms. It was concluded that, although the numbers and ty
pes of microbial population in domestic homes were high, they have lit
tle adverse effects on human health. (C) 1997 Elsevier Science Ltd.