Henry?s Law Constants and Indoor Partitioning of Microbial VolatileOrganic Compounds

Microbial volatile organic compounds (MVOCs)play an essential role in many environmentalfields, such as indoorair quality. Long-term exposure to odorous and toxic MVOCs cannegatively affect the health of occupants. Recently, the involvementof surface reservoirs in indoor chemistry has been realized, whichsignifies the importance of the phase partitioning of volatileorganic pollutants. However, reliable partition coefficients of manyMVOCs are currently lacking. Equilibrium partition coefficients,such as Henry's law constant,H, are crucial for understanding theenvironmental behavior of chemicals. This study aims toexperimentally determine theHvalues and their temperaturedependence for key MVOCs under temperature relevant to theindoor environment. TheHvalues were determined with the inert gas-stripping (IGS) method and variable phase ratio headspace(VPR-HS) technique. A two-dimensional partitioning model was applied to predict the indoor phase distribution of MVOCs andpotential exposure pathways to the residences. Thefindings show that the MVOCs are likely distributed between the gas and weaklypolar (e.g., organic-rich) reservoirs indoors. Temperature and the volume of reservoirs can sensitively affect indoor partitioning. Ourresults give a more comprehensive view of indoor chemical partitioning and exposure.