Do plants in an office have any effect on indoor air microorganisms?

The role of indoor plants as a source of microorganisms was studied in six office rooms.Concentrations of microorganisms (both fungi and actinomycetes) were determined fromindoor air and settled dust before the plants were placed in the office rooms and afterwardswith the plants in the rooms. Furthermore, samples of soil from the plant pots were analysed.Concentrations of airborne microorganisms were low during the whole study (< 100 cfu/cm).There was no increase in the concentration of indoor air microorganisms neither in theamount of microorganisms sampled from flat surfaces after the plants were placed in theoffice rooms. Trichoderma was the main fingal genus in the soil, while Penicillium,Cladosporium, non-sporing isolates and yeasts dominated in indoor air and surface samples.Trichoderma was not observed in indoor air or surface samples. The results indicate thatindoor plants are not a significant source of microorganisms.