This book provides an overview of state-of-the-art knowledge on emissions of chemical species and aerosols into the atmosphere. The papers are set in the wider context of other published work, providing comprehensive documentation of many aspects in this field of Earth science. The book is divided into 12 chapters, most dealing with inventories of emissions related to anthropogenic activities or biomass burning, emissions from vegetation and soils, emissions of mineral and sea-salt aerosols, and emissions of sulphur compounds from the oceans. The final three chapters show how atmospheric observations have been used to improve our knowledge of emissions, such as the use of isotopes, large observation networks as well as the latest inverse modelling techniques and their application to surface and satellite observations.