Measuring Hydrocarbons in the Atmosphere

Volatile organic compounds (VOCs) play a significant role in the chemistry of the troposphere. They are not only emitted into the atmosphere from a wide variety of natural and anthropogenic sources but they may also be formed via atmospheric transformations. Measurements of VOCs in the atmosphere have generally been made with gas chromatographic analyses of air samples collected in canisters, on adsorbents or in cryostats. These measurements give detailed information on a range of VOCs. However sampling times of several minutes are required for adsorbents and cryostats and so these methods are of little use if the atmospheric composition is rapidly changing. Canister samples can overcome this disadvantage but not all VOCs are quantitatively retained. The method is also time consuming and labor intensive. Recently, fast online methods for VOC determinations in particles by mass spectrometric methods have been developed.