Isotopic and chemical characterization of carbonaceous aerosols from anthropogenic sources

This thesis developed isotopic and chemical methods to investigate anthropogenic sources of carbonaceous aerosols. Chapters 2 and 3 solved the technical problems of 13C analysis of elemental carbon (EC) and total carbon (TC) by thermal-optical methods, including automated sample combustion as well as CO2 separation and purification. Based on this, the 13C source signatures of EC from combustion sources in China were determined. A comprehensive literature review of 13C source signatures (of raw materials and of aerosol TC and EC isolated using a variety of thermal methods) was conducted, and composite 13C source signatures of EC with uncertainties and detailed application conditions were recommended. These were applied to source apportionment of samples collected in Xi’an, China, during different seasons and pollution levels. Chapters 4 and 5 developed a new method to identify and quantify methylsiloxanes by mass spectrometry based on silicon isotope abundance. Using the new method, methylsiloxanes were investigated as indicators of anthropogenic sources in ship samples from Italy and tunnel samples from Brazil. New sources of methylsiloxanes in aerosols from traffic emissions were identified and quantified, i.e., ship and vehicle emissions.