This study investigated the presence of allergens such as dust and molds in heat recovery ventilation systems and the duct work. It also looks at two different types of cleaning equipment and their ability to clean these pollutants from the rigid and flexible ductwork and heat recovery ventilator (HRV) cores in dedicated balanced supply and exhaust ventilation systems. Samples from the ductwork and cores of ten ventilation systems were tested for levels of dust and mold.
Three different techniques for reducing exposure to microorganisms were tested during remediation of moldy buildings. Concentrations of spores (fungi and actinomycetes) were determined by filter sampling before, during, and after remediation. The local exhaust method used for asbestos dismantling was the most effective control method. In the construction zone, concentrations of microorganisms were 4-25 times higher during remediation than before it. In the adjacent area no increase in concentrations was seen.