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This dataset is of the trace element composition (Al, Fe, P, Ca, Si) of suspended particulate matter samples collected in the Indian Ocean. Samples were collected in the upper 1000 m of the water column along U.S. CLIVAR/CO2 Repeat Hydrography meridional section IO9N in 2009 from the Bay of Bengal to the subtropical front. The eastern Indian Ocean and South Indian subtropical gyre are characterized by a transition from a biologically productive system with significant fluvial sediment transport and aerosol deposition in the Bay of Bengal to an oligotrophic gyre with potentially significant input of particles from continental margin sources but relatively low aeolian trace metal inputs. These data are the first ocean section of trace particulate chemistry in the South Indian and Southern Oceans. High resolution sampling in the upper ocean along CLIVAR sections provides an opportunity to determine likely sources for biogenic and lithogenic particles and investigate the processes that drive their cycling. Suspended particulate matter (SPM) was collected by pressure-filtering (<55 kPa, filtered compressed air) seawater through acid-washed, 0.4 μm track-etched polycarbonate filters (Millipore). Backing filters of mixed cellulose ester were used for even sample loading in polypropylene filter holders. The average filtration volume was 9 L. Filters were gently rinsed with deionized water adjusted to pH 8 with ammonium hydroxide (3 x ~5 mL) with a low vacuum applied while avoiding loss or redistribution of particles in order to remove residual seasalt, avoiding salt interferences in ED-XRF analyses. SPM samples were analyzed using energy-dispersive x-ray fluorescence (ED-XRF) on a Thermo Fisher Quant’X under a vacuum atmosphere and calibrated with both commercial and custom made thin film standards.
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A Novel Method for Carbonate Quantification in Atmospheric Particulate Matter
Inorganic carbonate can be an important component of atmospheric particulate matter in arid environments where mineral dust components contribute significantly to air particulate matter. Carbonate carbon (CC) is only rarely quantified in atmospheric studies and methods to quantify carbonate in atmospheric samples are rare. In this manuscript, we present a novel protocol for quantifying carbonate carbon in atmospheric particulate matter samples, through the acidification of aerosol filters at ambient pressure and temperature and subsequent measurement of carbon dioxide (CO2) released upon acidification. This method is applicable to a variety of filter media used in air pollution studies, such as Teflon, cellulose, or glass fiber filters. The method allows the customization of the filter area used for analysis (up to 24 cm2) so that sufficient CO2 can be detected when released and to assure that the sample aliquot is representative of the whole filter. The resulting detection limits can be as low as 0.12 µg/cm2. The analysis of a known amount of sodium bicarbonate applied to a filter resulted in a relative error within 15% of the known mass of bicarbonate when measured 20 min after acidification. A particulate matter sample with aerodynamic diameter larger than 2.5 µm (PM>2.5) collected via cascade impaction on a high-volume aerosol sampler yielded good precision, with a CC concentration of 4.4 ± 0.3 µgC/cm2 for six replicates. The precision, accuracy, and reproducibility of this method of CC measurement make it a good alternative to existing quantification methods.
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- Award ID(s):
- 1832016
- PAR ID:
- 10200385
- Date Published:
- Journal Name:
- Atmosphere
- Volume:
- 11
- Issue:
- 6
- ISSN:
- 2073-4433
- Page Range / eLocation ID:
- 661
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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This dataset is of the trace element composition (Al, Fe, P, Ca, Si) of suspended particulate matter samples collected in the Indian Ocean. Samples were collected in the upper 1000 m of the water column along U.S. CLIVAR/CO2 Repeat Hydrography zonal section I05 in 2009 in the South Indian subtropical gyre. The eastern Indian Ocean and South Indian subtropical gyre are characterized by a transition from a biologically productive system with significant fluvial sediment transport and aerosol deposition in the Bay of Bengal to an oligotrophic gyre with potentially significant input of particles from continental margin sources but relatively low aeolian trace metal inputs. These data are the first ocean section of trace particulate chemistry in the South Indian and Southern Oceans. High resolution sampling in the upper ocean along CLIVAR sections provides an opportunity to determine likely sources for biogenic and lithogenic particles and investigate the processes that drive their cycling. Suspended particulate matter (SPM) was collected by pressure-filtering (<55 kPa, filtered compressed air) seawater through acid-washed, 0.4 μm track-etched polycarbonate filters (Millipore). Backing filters of mixed cellulose ester were used for even sample loading in polypropylene filter holders. The average filtration volume was 9 L. Filters were gently rinsed with deionized water adjusted to pH 8 with ammonium hydroxide (3 x ~5 mL) with a low vacuum applied while avoiding loss or redistribution of particles in order to remove residual seasalt, avoiding salt interferences in ED-XRF analyses. SPM samples were analyzed using energy-dispersive x-ray fluorescence (ED-XRF) on a Thermo Fisher Quant’X under a vacuum atmosphere and calibrated with both commercial and custom made thin film standards.more » « less
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- Free Publicly Accessible Full Text
-
Accepted Manuscript
- Journal Article:
- https://doi.org/10.3390/atmos11060661
