Indoor air quality impacts of ventilation ducts: ozone removal and emissions of volatile organic compounds.

The emission rate of VOCs and aldehydes from materials typically found in ventilation ducts was measured. It was found to be low for some duct liners, but high for duct sealing caulk and a neoprene gasket - in fact approaching the odour threshold. Exposure to ozone was found to increase the emission rate of aldehydes from a duct liner, duct sealing caulk and neoprene gasket. When exposed to ozone, the removal efficiency for a lined duct diminished to less than 4% over 10 days. It was much lower for an unlined duct. Concludes that ducts in ventilation systems are not likely to be a major sink for ozone.