The inhalation of harmful airborne particles may result in adverse health conditions and pathological changes in the respiratory tract. It is often seen that noxious inhaled particles activate an inflammatory pulmonary response, which can initiate a sub-chronic or chronic pulmonary disease. These conditions may include silicosis, pneumonitis, chronic obstructive pulmonary disease, asbestosis, emphysema, fibrosis, asthma or cancer. The severity of a particle-induced pathology is dependent on the exposure time and concentration as well as particle size, structure and composition. Airborne particles may include combustion-derived particles from welding, cigarette smoke, traffic and industry, etc. as well as biological particles such as pollen and fungi. Research on particle toxicology attempts to investigate the effects of individual particles and sources. This enables better predictability of newly generated particles. In vivo toxicological studies screen for long-term effects in the respiratory tract. Such studies include the histopathological analysis of the lungs for investigating adverse effects of particles. This book provides comprehensive insights into the field of particle toxicology. The topics included herein are of utmost significance and bound to provide incredible insights to readers. It will prove to be immensely beneficial to students and researchers in toxicology.