Inhalation of airborne contaminants including gases, vapours, aerosols and mixtures of these are significantly associated with both acute and chronic health effects but, the precise mechanisms that
derive such effects are not fully understood. Considering there are approximately 80,000 chemicals in commerce, and an extremely large number of chemical mixtures, conventional in vivo animal
toxicity testing of this large number of chemicals is unachievable from ethical, scientific, economic
and practical perspectives. Inhalation is considered the most important means by which humans are exposed to airborne chemicals however, inhalation studies are technologically more complicated than standard toxicity testing. Therefore, there is a need to explore new alternative approaches to provide toxicity data by developing in vitro techniques that are comparable to in vivo environments
during inhalation exposures.