The qualitative and quantitative capabilities of ion mobility spectrometry (IMS) as a comprehensive and powerful tool in workplace air monitoring have been demonstrated on the example of a Spanish pharmaceutical company. The developed IMS based procedure is capable of detecting and determining in air samples the active pharmaceutical ingredients (APIs) manipulated and/or produced in this pharmaceutical industry. Sensitivity, in the ng-pg range, selectivity, possibly to provide results in near real time, and reduction of analysis costs are the most important properties that ratify IMS as a serious alternative in occupational exposure assessment. The possibility of false positives by drift time interferences and false negatives by competitive ionization and also desorption process interferences has been deeply evaluated. Moreover, chemometric strategies based on self-modeling curve resolution (SMCR) have been applied to obtain qualitative and quantitative individual component information from overlapped peaks. The IMS procedure has been successfully applied to evaluate the concentration of APIs (nimesulide, dexketoprofen, deflazacort) handled by the pharmaceutical company employees in the making of tablets and granulates, and control measures have been suggested in accordance. © 2012 American Chemical Society.