James D. Allan

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A new technique has been developed to deconvolve and quantify the mass concentrations of hydrocarbon-like and oxygenated organic aerosols (HOA and OOA) using highly time-resolved organic mass spectra obtained with an Aerodyne Aerosol Mass Spectrometer (AMS). This technique involves a series of multivariate linear regressions that use mass-to-charge ratios(More)
[1] The aerosol mass spectrometer (AMS), manufactured by Aerodyne Research, Inc., has been shown to be capable of delivering quantitative information on the chemical composition and size of volatile and semivolatile fine airborne particulate matter with high time resolution. Analytical and software tools for interpreting the data from this instrument and(More)
The application of mass spectrometric techniques to the real-time measurement and characterization of aerosols represents a significant advance in the field of atmospheric science. This review focuses on the aerosol mass spectrometer (AMS), an instrument designed and developed at Aerodyne Research, Inc. (ARI) that is the most widely used thermal(More)
Organic matter frequently represents the single largest fraction of fine particulates in urban environments and yet the exact contributions from different sources and processes remain uncertain, owing in part to its substantial chemical complexity. Positive Matrix Factorisation (PMF) has recently proved to be a powerful tool for the purposes of source(More)
Organic aerosol (OA) particles affect climate forcing and human health, but their sources and evolution remain poorly characterized. We present a unifying model framework describing the atmospheric evolution of OA that is constrained by high-time-resolution measurements of its composition, volatility, and oxidation state. OA and OA precursor gases evolve by(More)
N. Takegawa,1 Y. Miyazaki,1 Y. Kondo,1 Y. Komazaki,1 T. Miyakawa,1 J. L. Jimenez,2 J. T. Jayne,3 D. R. Worsnop,3 J. D. Allan,4 and R. J. Weber5 1Research Center for Advanced Science and Technology, University of Tokyo, Tokyo, Japan 2Department of Chemistry and CIRES, University of Colorado, Boulder, Colorado, USA 3The Center for Aerosol and Cloud Chemistry,(More)
This paper presents results of an aerosol chemical characterisation experiment conducted on the Island of Jeju, Korea, using a range of techniques for analysing inorganic and organic particle components. Sulphate and ammonium were biased toward the accumulation mode size ranges. Nitrate, sodium, calcium and chloride were found in the larger size ranges and(More)
Two Aerodyne Aerosol Mass Spectrometers (AMS) were deployed at three sites representing urban, semi-rural and rural areas during the Pacific 2001 experiment in the Lower Fraser Valley (LFV), British Columbia, Canada in August 2001. The AMS provides on-line quantitative measurements of the size and chemical composition of the non-refractory fraction of(More)
We present an analysis of recent field data to investigate the variation in the organic component of atmospheric aerosol and its behaviour in the moist environment. In all locations the degree of oxygenation of the organic material increases with photochemical age, as does the particulate hygroscopicity. These changes will generally occur in spatial scales(More)