Compositional Analysis of Size-Segregated Aerosol Samples

Cahill, Thomas A.; Wakabayashi, Paul

doi:10.1021/ba-1993-0232.ch007

Cited by 31 publications

(23 citation statements)

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“… Braaten and Cahill [1986] established that transported Asian soils in spring events at Mauna Loa contained significant fractions less than 0.1 μm diameter, which contrasts strongly with mass median diameter of 0.7 ± 0.1 for local Hawaiian dust reported by Perry et al [1999]. Transported Asian dust is also much smaller than typical North American dust, the latter being almost entirely in the size range between 2.5 and 1.5 μm [ Raabe et al , 1988; Cahill and Wakabayashi , 1993]. Asian dust events have a common source.…”

Section: Discussionmentioning

confidence: 98%

Asian aerosols in North America: Frequency and concentration of fine dust

2002

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[1] Using an elemental signature for Asian dust derived from events in April 1998, we probed a long-term set of routine aerosol samples to develop the first empirical assessment of the frequency and intensity of dust transport from Asia to midlatitude North America. Our data reveal a pattern of consistent, frequent transport that contradicts the episodic characterization derived from short-term studies and anecdotal reports. We find that fine (<2.5 mm) Asian dust is a regular component of the troposphere over the eastern Pacific and western North America and is common, at least in spring, across North America. Typical Asian fine dust concentrations (24-hour average) are between 0.2 and 1 mg/m 3 and only very rarely exceed 5 mg/m 3 . Our data also indicate that Asian dust is concentrated in an altitude zone ranging from about 500 to 3000 m MSL, consistent with isentropic transport processes previously observed in the western Pacific.

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Section: Discussionmentioning

confidence: 98%

Asian aerosols in North America: Frequency and concentration of fine dust

2002

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“…The TRAC samplers deposited particles onto prearranged microscopy substrates that were automatically replaced every 15 min. Bulk particulate matter was continuously collected onto Teflon strips using a three-stage Davis Rotating drum Universal size-cut Monitoring (DRUM) impactor (Cahill and Wayakabashi, 1993). After collection, the exposed substrates were sealed and stored pending analyses.…”

Section: Sampling Sites and Particle Collectionmentioning

confidence: 99%

Microscopic characterization of carbonaceous aerosol particle aging in the outflow from Mexico City

et al. 2010

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Abstract. This study was part of the Megacities Initiative: Local and Global Research Observations (MILAGRO) field campaign conducted in Mexico City metropolitan area during spring 2006. The physical and chemical transformations of particles aged in the outflow from Mexico City were investigated for the transport event of 22 March 2006. A detailed chemical analysis of individual particles was performed using a combination of complementary microscopy and micro-spectroscopy techniques. The applied techniques included scanning transmission X-ray microscopy (STXM) coupled with near edge X-ray absorption fine structure spectroscopy (NEXAFS) and computer controlled scanning electron microscopy with an energy dispersive X-ray analyzer (CCSEM/EDX). As the aerosol plume evolves from the city center, the organic mass per particle increases and the fraction of carbon-carbon double bonds (associated with elemental carbon) decreases. Organic functional groups enhanced with particle age include: carboxylic acids, alkyl groups, and oxygen bonded alkyl groups. At the city center (T0) the most prevalent aerosol type contained inorganic species (composed of sulfur, nitrogen, oxygen, and potassium) coated with organic material. At the T1 and T2 sites, located northeast of T0 (∼29 km and ∼65 km, respectively), the fraction of homogenously mixed organic particles increased in both Correspondence to: M. K. Gilles (mkgilles@lbl.gov) size and number. These observations illustrate the evolution of the physical mixing state and organic bonding in individual particles in a photochemically active environment.

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“…Data reduction was performed offline using a well-accepted international XRF code, AXIL to generate the elemental profiles in 3-h temporal resolution. A detailed description of the sampling and analysis methods is provided by Cahill et al (1993).…”

Section: Sampling and Analysismentioning

confidence: 99%

Size-resolved source apportionment of ambient particles by positive matrix factorization at Gosan background site in East Asia

et al. 2006

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Abstract. Size-and time-resolved aerosol samples were collected using an eight-stage Davis rotating unit for monitoring (DRUM) sampler from 29 March to 29 May in 2002 at Gosan, Jeju Island, Korea, which is one of the representative background sites in East Asia. These samples were analyzed using synchrotron X-ray fluorescence for 3-h average concentrations of 19 elements consisting of S, Si, Al, Fe, Ca, Cl, Cu, Zn, Ti, K, Mn, Pb, Ni, V, Se, As, Rb, Cr, Br. The size-resolved data sets were then analyzed using the positive matrix factorization (PMF) technique in order to identify possible sources and estimate their contribution to particulate matter mass. PMF analysis uses the uncertainty of the measured data to provide an optimal weighting. Fifteen sources were resolved in eight size ranges (0.07∼12 µm) and included continental soil, local soil, sea salt, biomass/biofuel burning, coal combustion, oil heating furnace, residual oil fired boiler, municipal incineration, nonferrous metal source, ferrous metal source, gasoline vehicle, diesel vehicle, copper smelter and volcanic emission. PMF analysis of size-resolved source contributions showed that natural sources represented by local soil, sea salt and continental soil contributed about 79% to the predicted primary particulate matter (PM) mass in the coarse size range (1.15∼12 µm). On the other hand, anthropogenic sources such as coal combustion and biomass/biofuel burning contributed about 60% in the fine size range (0.56∼2.5 µm). The diesel vehicle source contributed the most in the ultra-fine size range (0.07∼0.56 µm) and was responsible for about 52% of the primary PM mass.

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Compositional Analysis of Size-Segregated Aerosol Samples

Cited by 31 publications

References 0 publications

Asian aerosols in North America: Frequency and concentration of fine dust

Asian aerosols in North America: Frequency and concentration of fine dust

Microscopic characterization of carbonaceous aerosol particle aging in the outflow from Mexico City

Size-resolved source apportionment of ambient particles by positive matrix factorization at Gosan background site in East Asia

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