Characterization and source apportionment of carbonaceous aerosols in China

Abstract

Carbonaceous aerosols (CAs) are a major contributor to air pollution and large uncertainties in climate radiative forcing. To reduce air pollution and improve our understanding of CAs’ role in climate change, this thesis therefore focuses on characterization and source apportionment of CAs and its carbon sub-fractions with a special focus on the situation and sources of China. In this context, different aspect of CAs are covered. First, seasonal changes in sources of CAs and its carbon sub-fractions are investigated based on one-year measurements of radiocarbon, a powerful source tracer. Then, the sources and atmospheric processing of CAs are studied in different geographical locations during wintertime when severe air pollution occurs frequently in China. Further, particular attention is paid to coal combustion, which is a major source of air pollution in China. Both directly emitted and atmospheric processed CAs from residential coal combustion is characterized by light absorption analysis to gain better insight into the climate impact of CAs. Findings from this thesis lead to better understanding of the sources and formation mechanisms of CAs, of CAs’ effects on climate change, and of how the atmospheric processes modify properties of CAs. With the increased knowledge of CAs, results from this thesis facilitate to develop control strategies to reduce air pollution and effects of CAs on climate, non only in China but in many regions where similar sources and processes play a role.