The layer of gases that surround a material body and are held together by the body's gravity is called its atmosphere. It works as a shield for living organisms and protects them from damage against cosmic rays, solar ultraviolet radiation and solar winds. Atmospheric science refers to the study of the Earth's atmosphere and the physical processes related to it. The discipline is divided into various sub branches, namely, atmospheric chemistry, atmospheric physics, atmospheric dynamics and climatology. Atmospheric chemistry is a multidisciplinary field which draws on the principles of physics, chemistry and meteorology to study the chemistry of the Earth's atmosphere. This book presents the complex subject of atmospheric sciences in the most comprehensible and easy to understand language. It elucidates new techniques and their applications in a multidisciplinary approach. This book is an essential guide for both academicians and those who wish to pursue this discipline further.