Mixtures of heterogeneous particles, individual molecules, and small aggregates suspended in the atmosphere ultimately deposit onto all of Earth’s solid surfaces. The resulting surface films act as environmental sinks, sources, and reaction centers, impacting fate and transport pathways. We present physical and chemical analyses of passively collected environmental films, aimed at understanding how a film’s morphology, spatial chemical profile, and maturation behavior can affect participation in fate and transport. We examine the surfaces’ physical morphology from millimeter to nanometer dimensions using bright-field, scanning electron, and atomic force microscopies. Chemical analysis maps are provided by energy dispersive x-ray spectroscopy and secondary ion mass spectrometry. Surface feature sizes span six orders of magnitude, indicative of super- and sub-micrometer PM as well as conformal films of nanoscale PM and semi volatile molecules. Our sampling sites and timeframe allow preliminary insights to characterize seasonal variations in film chemistry and anthropogenic influence of point sources such as biomass fired power plants.

Heterogeneity in urban environmental films

2019 Fall National Meeting

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