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Growth of organic films on indoor surfaces
Author(s) -
Weschler C. J.,
Nazaroff W. W.
Publication year - 2017
Publication title -
indoor air
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.387
H-Index - 99
eISSN - 1600-0668
pISSN - 0905-6947
DOI - 10.1111/ina.12396
Subject(s) - gas phase , volume (thermodynamics) , range (aeronautics) , growth rate , phase (matter) , materials science , chemistry , environmental chemistry , environmental science , thermodynamics , organic chemistry , composite material , physics , geometry , mathematics
Abstract We present a model for the growth of organic films on impermeable indoor surfaces. The model couples transport through a gas‐side boundary layer adjacent to the surface with equilibrium partitioning of semivolatile organic compounds ( SVOC s) between the gas phase and the surface film. Model predictions indicate that film growth would primarily be influenced by the gas‐phase concentration of SVOC s with octanol‐air partitioning ( K oa ) values in the approximate range 10≤log K oa ≤13. Within the relevant range, SVOC s with lower values will equilibrate with the surface film more rapidly. Over time, the film becomes relatively enriched in species with higher log K oa values, while the proportion of gas‐phase SVOC s not in equilibrium with the film decreases. Given stable airborne SVOC concentrations, films grow at faster rates initially and then subsequently diminish to an almost steady growth rate. Once an SVOC is equilibrated with the film, its mass per unit film volume remains constant, while its mass per unit area increases in proportion to overall film thickness. The predictions of the conceptual model and its mathematical embodiment are generally consistent with results reported in the peer‐reviewed literature.