Abstract
Precise characterization of sources of chemical compounds from the Earth's surface into the atmosphere is crucial information for air quality and climate models. In this chapter, we review the main sources of natural emissions including emissions from vegetation, soils, oceans, volcanoes, and emissions of dust.
Methodology for emission estimation is described for each source, identifying the main emitted chemical species and processes driving the emission. Examples of input information to the emission models are given together with global emission estimates and their spatiotemporal distribution.