Chemistry and Physics Faculty Articles

Document Type

Article

Publication Date

3-16-2011

Publication Title

Journal of Geophysical Research

Keywords

Saharan dust, African dust, Fog water, Non-sea-salt, Precipitation, Scavenging process

ISSN

0148-0227

Volume

116

Issue/No.

D5

First Page

1

Last Page

17

Abstract

Cloud water, rainwater, and aerosol particles were collected in Puerto Rico from December 2004 to March 2007 in order to investigate their chemical composition, relation to sources, and removal processes. The species analyzed were inorganic ions, metals, total and dissolved organic carbon (TOC, DOC), total nitrogen (TN), and organic acids. For all samples, the dominant species were marine (Na+, Cl), representing about 50%–65% of total content. Non‐sea‐salt fraction was dominated by SO42− (17%–25%), followed by water‐soluble organic (2%–8%) and total nitrogen (2% –6%) compounds. Organic acids represented contributions to the organic fraction in cloud water of 20% and 6% for aerosol particles. Inorganic species were predominant in total nitrogen portion. The chemical composition of cloud water, rainwater, and aerosol particles were observed to be sensitive to transport patterns. Air masses from northwest Africa showed the highest concentrations of nss‐Ca2+, Fe, and Al, suggesting a crustal origin. The pH values for cloud water and rainwater observed under this transport pattern were higher than background conditions, probably due to the alkalinity associated with nss‐Ca2+. The highest concentrations of Cl and SO42−, with lower pH, were measured during periods of influence from Soufriere Hills volcano eruptions, most likely due to emitted SO2 and HCl. Air masses from North America had an anthropogenic influence, where levels of nss‐SO42−, TOC, and TN were higher (∼4 times) than in clean air masses. These results suggest that long‐range transport could be an extra source of metals and organic/nitrogen species to the Caribbean region ecosystems.

Comments

©2011 by the American Geophysical Union.

Additional Comments

NSF grant #s: ATM-0342548, DEB 0620910

ORCID ID

0000-0002-0566-0820

ResearcherID

V-6501-2018

DOI

10.1029/2010JD015010

Peer Reviewed

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