Application of a mobile laboratory using a Selected-Ion Flow-Tube Mass Spectrometer (SIFT-MS) for characterisation of volatile organic compounds and atmospheric trace gases

Abstract. The importance of emissions source types in urban areas has undergone significant changes over the past two decades. In particular, there has been a considerable reduction in emissions associated with road vehicles. Understanding the role played by different source sectors is important if effective air pollution control is to be achieved. Current atmospheric measurements are made at fixed monitoring sites, most of which do not include the measurement of volatile organic compounds (VOCs) and so our understanding of the temporal and spatial variation of pollutants is limited. Here we describe the application of a mobile laboratory using a selected-ion flow tube mass spectrometer (SIFT-MS) and other trace gas instrumentation to provide on-road, high spatial and temporal resolution measurements of CO2, CH4, VOCs and other trace gases. We then present data illustrating the potential of this platform for developing source characterisation methods that account for the similarity in correlation between species. Finally, we consider the benefits of high spatial and temporal resolution measurements in characterising different types of source, which would be difficult or impossible for single species studies.