Stability of gaseous volatile organic compounds contained in gas cylinders with different internal wall treatments
George C. Rhoderick, Christina E. Cecelski, Walter R. Miller Jr., David Worton, Sergi Moreno, Paul Brewer, Joele Viallon, Faraz Idrees, Philippe Moussay, Yong D. Kim, Dal H. Kim, Sangil Lee, Annarita Baldan, Jianrong Li
Volatile organic compounds (VOCs) are a group of gas-phase compounds present in the atmosphere that affect air quality and Earths climate. Halocarbons, a subset of this group, are strong greenhouse gases and are linked to stratospheric ozone depletion. Other subsets of VOCs are hydrocarbons that include alkanes, alkenes and simple aromatics. Monoterpenes, oxygenates, formaldehyde and dimethyl sulfide are also important VOCs in atmospheric chemistry. These are precursors and contributors to atmospheric photochemical processes that lead to the formation of particulates and secondary photo-oxidants, such as ozone, resulting in photochemical smog. Measurements of VOCs in the atmosphere have been ongoing for decades to track growth rates and assist in curbing emissions of these compounds into the atmosphere. To accurately establish mole fraction trends and assess the role of these gas-phase compounds in atmospheric chemistry it is essential to have good calibration standards. A necessity and precursor to accurate VOC gas standards are the gas cylinders and the internal wall treatments that aid in maintaining the stability of the mixtures over long periods of time, measured in years. This paper will discuss the stability of VOC gas mixtures in different types of gas cylinders and internal wall treatments.