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An on-line instrument for mobile measurements of the spatial variability of hexavalent and trivalent chromium in urban air

dc.contributor.author Khlystov, Andrey
dc.contributor.author Ma, Yilin
dc.date.accessioned 2013-04-01T14:37:49Z
dc.date.issued 2006
dc.identifier.issn 1352-2310
dc.identifier.uri https://hdl.handle.net/10161/6452
dc.description.abstract The Steam-Jet Aerosol Collector-long Pathlength Absorbance Spectroscopy (SJAC-LPAS), an on-line continuous instrument for mobile measurements of spatial distribution of water-soluble hexavalent and trivalent chromium in ambient aerosols, has been developed and is presented here. The system collects particles with the SJAC and analyzes the collected sample on-line using the diphenycarbazide (DPC) colorimetric method. By using a Teflon AF (Amorphous Fluoropolymer) liquid core wave guide, the limit of detection has been significantly improved, allowing on-line measurements at ambient concentrations. The limit of detection for Cr(VI) is 0.2 ng m(-3). Water-soluble Cr(III) can also be measured by oxidizing it to Cr(VI) in a parallel line using hydrogen peroxide before the detection with the DPC method. The concentration of Cr(III) is then determined as the difference between the two lines (Cr(VI) and Cr(VI) plus Cr(III)). The instrument was specifically designed to be used on a mobile platform to study spatial distribution of the pollutant within a city on a scale of 100 m. Special attention was given to the time resolution and the stability of the instrument performance under driving conditions. The time resolution of the instrument is 15 s. At a typical driving speed of 30 km h(-1) the instrument can detect variations in chromium concentration ({''}hot spots{''}) on the scale of about 150 m. The instrument has proven to operate reliably and capture temporal and spatial variability of Cr(VI) concentration during four mobile measurement campaigns in Wilmington, DE. (c) 2006 Elsevier Ltd. All rights reserved.
dc.publisher Elsevier BV
dc.relation.ispartof ATMOSPHERIC ENVIRONMENT
dc.title An on-line instrument for mobile measurements of the spatial variability of hexavalent and trivalent chromium in urban air
dc.type Journal article
duke.contributor.id Khlystov, Andrey|0312531
pubs.begin-page 8088
pubs.end-page 8093
pubs.issue 40
pubs.organisational-group Duke
pubs.organisational-group Faculty
pubs.publication-status Published
pubs.volume 40


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