Several areas of advanced research related to sampling, analysis, and human exposure assessment of exhaust emission in ambient air have been developed. These include studies of new methods for volatile organic compounds (VOC's), and the development and application of personal exposure monitors (PEM's) in screening for polynuclear aromatics (PNA's) and carbon monoxide (CO). These new methods for screening PNA's are fast, economical and accurate. The more expensive and time consuming traditional methods of analysis may be judiciously applied to those samples which the screening methods indicate are high in PNA's. Carbon monoxide, an emission product directly related to automotive emissions, is being monitored using personal exposure monitors in urban scale studies to obtain data on population exposures on a real time basis. Such data may ultimately be used in assessing more accurately human exposure to mobile source and other emissions.