Natural catastrophic events such as volcano eruptions have greatly affected environments in wide regions around the world. Ash and gases impelled by these eruptions into the atmosphere carry large volumes of particles of different sizes (nanometer and ultrafine) that are scattered around the earth. However, the greater accumulation of different grain size was observed in the range of 10 kilometres from the centre of the volcano, causing devastating effect. The most important consequences of this type of event are loss of habitats for flora and fauna. This book discusses the triggers of volcanic eruptions, as well as environmental effects and the role they play in climate change.