Microbial air quality in offices at municipal landfills

The purpose of this study was to evaluate the influence of two municipal landfills on the microbiological air quality in offices on landfill sites. The evaluation was based on the concentration levels of airborne bacteria and fungi and the identification of isolated strains. Air samples were collected with a six-stage Andersen impactor. The concentrations of bacterial aerosol ranged from 1.0 x 10(3) to 7.2 x 10(4) colony forming units (CFU)/m(3) indoors, and from 7.0 x 10 to 4.0 x 10(4) CFU/m(3) outdoors. The corresponding fungal aerosol ranges were from 2.3 x 10(2) to 7.3 x 10(3) CFU/m(3) indoors and from 2.0 x 10(2) to 1.2 x 10(4) CFU/m(3) outdoors. The concentration levels were affected by the season of the year. The study showed that both indoor and outdoor air were heavily contaminated with bacteria and fungi. The proximity of the unpaved transport route and the weighing of refuse loads contributed to the increase of bacterial and fungal aerosol concentrations significantly. The air in the offices was characterized not only by elevated concentrations of bacteria and fungi but also by high frequencies of gram-negative bacteria, along with fungal species characteristic of landfills. The quantitative and qualitative changes in the composition of the bacterial and fungal aerosol posed a possible health risk to office workers at municipal waste landfill sites.