Bioaerosol and particle mass levels and ventilation in Finnish homes

Abstract Fungal spore, bacteria, and total particle mass concentrations were monitored inside and outside apartments in buildings with different ventilation systems by otherwise of similar design. Concentration levels were determined before the tenants moved in and later at different periods. The sampling was based on six-stage impactors for spores and bacteria and Nuclepore filters for total particle mass. The results after the first year of occupancy showed that the mechanical supply and exhaust ventilation system decreases indoor levels of fungal spores. The decrease is not as evident for bacteria or total particle mass. The effect of occupancy could, however, be seen on indoor bacteria and total particle mass levels.