Climate change is one of the biggest challenges facing the world in the 21st century. Human activities, like combustion of fossil fuel result in emissions of different radiation-modifying substances like aerosol particles and greenhouse gases that have a profound influence on our climate system through either by warming or cooling earth's surface. Green leaf volatiles (GLVs) are an important component of biogenic volatile organic compounds (BVOCs) released by vegetation during mechanical damage, herbivory attack, pathogen infection and abiotic stress. They play a major role in contributing to the formation of secondary organic aerosol particles in atmosphere. The main objective of this book was to examine the formation of secondary organic aerosol particles from ozonolysis of various GLVs (trans-2-hexenal, cis-3-hexenol and 3-hexynyl acetate) by using series of chamber experiments performed in humid conditions (~50% RH).