Epidemiological studies have shown that inhalation of soot particles can cause pulmonary disease, cardiovascular damage and mortality. New findings show soot may be contributing to changes happening near the North Pole, such as accelerating melting of sea ice and snow and changing atmospheric temperatures. Soot surface chemistry may determine whether it can act as cloud nuclei, its participation in atmospheric heterogeneous reactions, thereby significantly affecting the atmospheric radiative balance. These properties are further modified by soot's nanostructure, along with its oxidation characteristics. With increasing knowledge of the detrimental health effects of soot and environmental impacts, identification of emission sources is of increasing importance

Electron microscopic and spectroscopic methods have great potential for carbonaceous aerosol characterization. High-resolution transmission electron microscopy (HRTEM) provides information of the carbon nanostructure (or relative lack thereof). Image quantification allows extraction of various statistical parameters including lamella length, separation distance and tortuosity. These may be summarized in the form of histograms. X-ray photoelectron spectroscopy (XPS) provides a means for probing the surface chemistry of materials. It provides not only information about the atomic composition of a sample but also information about the structure and oxidation state of the constituent elements.

Combustion produced soot is a highly variable material. Physically the nanostructure can range from amorphous to graphitic to fullerenic. Chemically nearly any element could be included, though the surface functional groups are predominantly oxygen-based. Results will be presented for analysis of HRTEM images of the physical nanostructure and XPS analysis of the chemical composition of soots collected from plant, institutional and residential scale oil-fired boilers, diesel engine, gas-turbine combustor (jet) and a wildfire. Physically soots from these emission source classes may be differentiated based on carbon lamella length, mean separation and tortuosity. Chemically these soots may also be distinguished by elemental composition, surface (oxygen) functional groups and carbon bonding.

Characterization of source (particulate) emission profiles is integral to formulation of source profiles towards development of receptor-based models and extraction of source contributions to monitored sites. Atmospheric and local environmental impacts can then be accurately assessed. Regulatory statutes may be specifically targeted. Human exposure and related health effects can be accurately evaluated.