Recent field studies of the air quality in transportation cabins are summarized in this paper. Overall, very limited field data are available to the public. A comparison of the methodologies showed that no common instrumentation was used in the field measurements, even for identical indoor air quality parameters. Therefore, care should be exercised when comparing the results from different studies. Most of the air contaminant concentrations in airplanes were below the threshold values during cruising and in nonsmoking environments but could reach higher levels for noncruising periods and smoking environments. The air quality in passenger vehicles varied significantly with the ventilation mode, weather, and traffic. In summary, there were limited field data available in ground transportation cabins, and no data have been reported for commercial truck cabins.