Air-liquid interface (ALI) systems have been widely used in recent years to investigate the inhalation toxicity of many gaseous compounds, chemicals, and nanomaterials and represent an emerging and promising method to supplement studies. ALI exposure reflects the physiological conditions of the deep lung more closely to subacute inhalation scenarios compared to submerged exposure. The comparability of the toxicological results obtained from and inhalation data is still challenging. The robustness of ALI exposure scenarios is not yet well understood, but critical for the potential standardization of these methods. We report a cause-and-effect (C&E) analysis of a flow through ALI exposure system. The influence of five different instrumental and physiological parameters affecting cell viability and exposure parameters of a human lung cell line (exposure duration, relative humidity, temperature, CO concentration and flow rate) was investigated. After exposing lung epithelia cells to a CeO nanoparticle (NP) aerosol, intracellular CeO concentrations reached values similar to those found in a recent subacute rat inhalation study . This is the first study showing that the NP concentration reached using a flow through ALI system were the same as those in an study.