Cyclic siloxanes are chemicals present in personal care products such as antiperspirants and hair conditioners. Past research of the ecological and health consequences of these chemicals has neglected the possibility of reactions that lead to airborne silicon nanoparticles. The goal of this thesis is to understand the chemistry and implications of cyclic siloxane reaction and nanoparticle generation. Characterization of the silicon nanoparticles, and atmospheric modeling to predict concentrations and spatial distribution have been performed.