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Different on-line submicron particle sizing techniques report different " equivalent diameters. " For example, differential mobility analyzers (DMAs) report electrical mobility diameter (d m), while a number of recently developed instruments (such as the Aero-dyne aerosol mass spectrometer, or AMS) measure vacuum aerodynamic diameter (d va). Particle(More)
Citation Ng, N. L. et al. " Organic aerosol components observed in Northern Hemispheric datasets from Aerosol Mass Spectrometry. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Abstract. In this study we compile and present results from the factor analysis of 43 Aerosol Mass Spectrometer(More)
[1] The Aerodyne Aerosol Mass Spectrometer (AMS) has been designed to measure size-resolved mass distributions and total mass loadings of volatile and semivolatile chemical species in/on submicron particles. This paper describes the application of this instrument to ambient aerosol sampling. The AMS uses an aerodynamic lens to focus the particles into a(More)
Submicron aerosol was analyzed during the MI-LAGRO field campaign in March 2006 at the T0 urban super-site in Mexico City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and complementary instrumentation. Mass concentrations, diurnal cycles , and size distributions of inorganic and organic species are similar to results from the(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)
Size-resolved indicators of aerosol acidity, including H+ ion concentrations (H+Aer) and the ratio of stoichiometric neutralization are evaluated in submicrometer aerosols using highly time-resolved aerosol mass spectrometer (AMS) data from Pittsburgh. The pH and ionic strength within the aqueous particle phase are also estimated using the Aerosol(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)
Recent field studies have found large discrepancies in the measured vs. modeled SOA mass loadings in both urban and regional polluted atmospheres. The reasons for these large differences are unclear. Here we revisit a case study of SOA formation in Mexico City described by Volka-mer et al. (2006), during a photochemically active period when the impact of(More)
[1] The sources of secondary organic aerosol (SOA) are highly uncertain. Direct measurements of gas-phase glyoxal in Mexico City are compared to experimentally constrained model predictions. Observed glyoxal concentrations are found significantly below those predicted. Additional glyoxal sources are likely and would increase these differences; an additional(More)
Atmospheric aerosol particles serving as cloud condensation nuclei (CCN) are key elements of the hydrological cycle and climate. We have measured and characterized CCN at water vapor supersaturations in the range of S=0.10–0.82% in pristine tropical rainforest air during the AMAZE-08 campaign in central Amazonia. The effective hygroscopicity parameters(More)