Heterogeneous Soot Nanostructure in Atmospheric and Combustion Source Aerosols

Abstract

In this work, high-resolution transmission electron microscopy images of microscopic soot emissions from wildfire and from a wide range of anthropogenic combustion sources (e.g., electrical utility and institutional oil boilers, jet aircraft, and heavy-duty diesel trucks) are presented. The soot nanostructures of individual particles in these emissions are predominantly heterogeneous, decidedly influenced by the fuel composition and by the particular combustion process the fuels undergo, and reveal the mechanisms underlying primary soot particle inception and growth. A lattice fringe analysis shows that differences among the soot nanostructures are measurable. To study whether these differences might identify the combustion source types contributing to ambient aerosols, we also examine the nanostructures of individual atmospheric particles collected at two spatially diverse United States locations (Duke Forest, North Carolina, and the Northern Front Range, Colorado). We find that the elemental carbon stru...