The Environmental Monitoring Systems Laboratory (EMSL), U.S. EPA, is currently funding research programs to develop reference and audit standards to evaluate performance and data quality of air monitoring measurements for volatile organic compounds. As a result of this effort, which is being conducted by the National Bureau of Standards (NBS), single component (benzene, tetrachloroethylene) and multicomponent (aromatic hydrocarbons) blends in gas cylinders have been certified as Standard Reference Materials (SRM's) at ppm concentrations. A multicomponent cylinder mixture of aliphatic chlorocarbons is in the process of being certified as an SRM. NBS specially prepared and analyzed a cylinder gas mixture containing volatile organic compounds at ppb concentrations so that three ambient air monitoring and analytical systems could be evaluated during a field study. The availability of traceable standards at ppb concentration allows the performance of air sampling systems to be evaluated at actual measurement levels of the pollutants. Volatile organics in the low ppb range have also been prepared as traceable audit materials for the assessment of hazardous waste incinerator pollutants. Future development of reference materials will include the preparation of other chemical classes (ketones, nitrogencontaining compounds) and deuterated compounds in cylinders. These latter materials will be used to determine the sampling efficiencies of solid adsorbants.