Deposition of Organic Films and Particles on Indoor-Air Surfaces

Surfaces play a crucial role in the indoor environment. Partitioning of gaseous and particulate matter onto these surfaces significantly influences  the lifetime and reactivity of indoor compounds. Compared to outdoors,  indoor environments are characterized by significantly larger surface-to-volume ratios, lower air exchange rates, and higher concentrations of volatile organic compounds and particulate matter. Thus, indoor surfaces play a large role in the chemistry encompassed within buildings, whereon organics and particles can be adsorbed, transformed, and desorbed.  Indoor surfaces are highly diverse,  stemming from carpets and furniture to window glass and even human skin. Additionally, the types of deposited films and particles a surface is subject to is extremely diverse and heavily depends on the emitting objects and activities associated with the local environment surrounding the surface - ranging from oils and combustion byproducts from cooking to metal oxide nano-particles and polyaromatic hydrocarbons from printer emissions. 

The Grassian group studies and characterizes deposited species on the indoor-surfaces using surface sensitive techniques AFM-PTIR and nano-DESI MS. AFM-PTIR provides valuable insight on the size, morphology, and chemical composition, and studies utilizing nano-DESI MS enables quantitative composition analyses of deposited species. By applying these techniques to our library of authentic indoor surfaces,  the Grassian group provides a more detailed picture on what compounds are being  preferentially adsorbed, dependencies of deposited compound variations on local environments or different surfaces, and potential transformative processes occurring at the air/surface interface.