The diagnosis and management of pulmonary disease would benefit tremendously from an improved understanding of causative factors and underlying disease mechanisms. Environmental endotoxin exposures are known to cause human respiratory health effects, but research studies in this area are hampered by lack of reproducible, standardized methods for measurement of environmental endotoxin. Additionally, a non-invasive method of assessing airway inflammation in response to environmental respiratory exposures is currently needed. In this research study, we aimed to improve our ability to reliably measure the exposure of environmental endotoxin and investigate the utility of a novel, non-invasive method used for collection and measurement of inflammatory biomarkers in human exhaled breath.;To accomplish these aims, we evaluated the effect of four assay buffers on reproducibility and correlation of endotoxin measurements in house dust samples using three lots of commercially available assay for environmental endotoxin exposure. Additionally, we developed and optimized methods for collection, recovery and detection of aerosolized human cytokines using a single-pass aerosol chamber and filter collection device. Finally, we applied these newly developed methods to the collection, recovery and detection of cytokines in human exhaled breath samples to demonstrate proof-of-concept of a new non-invasive lung monitoring technique.;The results of this study indicated that use of either a commercially available Tris-based buffer or water in rFC assays may improve assay reproducibility and correlated well with other methods used to measure environmental endotoxin exposure. Aerosols of human cytokines were generated and successfully collected using TeflonRTM filters. Analyses of cytokine measurements made using our new collection methods suggest filter-based collection techniques can be utilized to evaluate inflammatory biomarkers in human exhaled breath samples. Taken together, the findings of our study offer improved reliability for measurement of environmental endotoxin exposure and represent a potentially promising new tool for the study of inflammatory biomarkers in exhaled breath samples.