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Determination of partition and diffusion coefficient of formaldehyde in selected building materials and impact of relative humidity
Xu, J., J. S. Zhang, AND X. LIU. Determination of partition and diffusion coefficient of formaldehyde in selected building materials and impact of relative humidity. In Proceedings, Indoor Air 2011, Austin, TX, June 05 - 10, 2011. International Society of Indoor Air Quality and Climate (ISIAQ), Santa Cruz, CA, 7 p, (2011).
The partition and effective diffusion coefficients of formaldehyde were measured for three materials (conventional gypsum wallboard, "green" gypsum wallboard, and "green" carpet) under three relative humidity (RH) conditions (20%, 50% and 70% RH). A dynamic dual-chamber test method was used. Results showed that a higher relative humidity led to a larger effective diffusion coefficient for both conventional wallboard and green wallboard. The partition coefficient (Kma) of formaldehyde in conventional wallboard was larger at 50% RH than at 20% RH, while the difference in Kma between 50% RH and 70% RH was insignificant. For the green wallboard and green carpet, the partition coefficient increased slightly with the increase of relative humidity from 20% to 50% and then to 70%. The carpet was also found to be very permeable resulting in a diffusion coefficient at the same level as the formaldehyde diffusion coefficient in air. The data generated could be used to assess the sorption effects of formaldehyde on building materials and to evaluate its impact on the formaldehyde concentration in buildings.