Effect of heating-ventilation-air conditioning system sanitation on airborne fungal population in residential environments.

Study aimed to assess the effectiveness of domestic air duct sanitation services in reducing indoor aeroallergens. Sampling for fungal colony forming units was carried out in eight residences in winter and seven in summer, before and after a local company carried out duct sanitation procedures. Two houses were used as controls. Baseline CFUs were similar in control and study houses. The study homes showed an overall CFU reduction of 92% in winter and 84% in summer, eight weeks after cleaning. The controls showed no reduction. In addition it was found that the cleaning procedure appeared to reduce the number of fungal colonies entering and leaving the HVAC system, implying that the system itself held a significant percentage of the total fungal load in the houses. Concludes that HVAC sanitation may be an effective tool in reducing airborne fungal populations in domestic environments.