Developments in Hydrocarbon Gas Standards at NIST: Supporting the World Meteorological Organization Measurement Infrastructure

There has been increased recognition of the diverse influence of hydrocarbons on atmospheric chemistry and climate, including their roles in secondary organic aerosol formation, ozone production, and the oxidative capacity of the atmosphere. This has led to considerable interest in measuring ambient concentrations of these species and, in particular, emission rates of monoterpenes from terrestrial vegetation. In order to establish accurate measurement records, and to relate those records amongst various laboratories, it is essential to have reliable calibration standards. The National Institute of Standards and Technology (NIST), which serves as the World Meteorological Organization (WMO) Central Calibration Laboratory (CCL) for monoterpenes, has developed a suite of monoterpene standards in support of the WMO Global Atmosphere Watch (GAW) program for volatile organic compounds (VOCs). NIST also supports hydrocarbon standards for the WMO-GAW through comparisons with the UK's National Physical Laboratory (NPL), the WMO CCL for hydrocarbons. Finally, NIST has implemented an international key comparison for monoterpenes, deemed CCQM-K121. The objective of this key comparison is to enable the evaluation of international measurement standards, as well as to support calibration and measurement capabilities for VOC gas mixtures.