HR: 1340h
AN: A23D-1574    [Abstracts]
TI: Cloud water and aerosol studies in a background marine environment
AU: * Gioda, A
EM: adriana@adam.uprr.pr
AF: University of Puerto Rico, ITES and Department of Chemistry, San Juan, PR 00931,
AU: Mayol-Bracero, O L
EM: omayol@adam.uprr.pr
AF: University of Puerto Rico, ITES and Department of Chemistry, San Juan, PR 00931,
AU: Reyes-Rodriguez, G
EM: gabillo2000@hotmail.com
AF: University of Puerto Rico, ITES and Department of Chemistry, San Juan, PR 00931,
AU: Santos-Figueroa, G
EM: gilmarie17@hotmail.com
AF: University of Puerto Rico, ITES and Department of Chemistry, San Juan, PR 00931,
AU: Morales-de Jesus, R
EM: rjmorales@uprrp.edu
AF: University of Puerto Rico, Physical Sciences Department, San Juan, 00931,
AU: Collett, J
EM: collett@lamar.colostate.edu
AF: Colorado State University, Department of Atmospheric Science, Fort Collins, CO 80525,
AU: Decesari, S
EM: s.decesari@isac.cnr.it
AF: Institute of Atmospheric Science and Climate, CNR, Bologna, 40100, Italy
AU: de Aquino Neto, F R
EM: radler@iq.ufrj.br
AF: Federal University of Rio de Janeiro, LADETEC, Rio de Janeiro, BRA 21941-909,
AU: Klaus, C
EM: cklaus@iq.ufrj.br
AF: Federal University of Rio de Janeiro, LADETEC, Rio de Janeiro, BRA 21941-909,
AU: Bezerra, H
EM: agioda@hotmail.com
AF: Federal University of Rio de Janeiro, LADETEC, Rio de Janeiro, BRA 21941-909,
AB: The study of aerosol and cloud water chemical composition is essential to understand cloud processing of different compounds, determining which species are more efficiently removed and which ones stay longer in the atmosphere and, therefore, are more important for aerosol climate forcing. As part of the Rain In Cumulus over the Ocean Experiment (RICO), cloud water and aerosol samples were collected in Puerto Rico. We present concentrations of water-soluble ions, total and dissolved organic carbon (TOC and DOC), total nitrogen (TN), and the speciation of nitrogen compounds (amino acids) for water and aerosol samples collected at East Peak and Cape San Juan, Puerto Rico. Mass and elemental/organic carbon (EC, OC) concentrations were also determined for the aerosol samples. The results show average concentrations of TOC and TN in cloud water of about 1.1 mg/L and for DOC about 0.9 mg/L. The DOC/TOC ratio averaged 0.78, indicating that most of the organic compounds present are dissolved in the cloud water. TOC was composed mainly of organic acids (47 percent) and TN of inorganic species (80 percent). With respect to the aerosol samples, the average mass concentration of fine particles (Dp < 1.7 um) was 2.4 ug/m3. EC was found at low-to-non detectable levels (< 0.5 ng/m3). The concentrations of OC, DOC, TOC, and TN ranged from 30 to 100 ng/m3. The size distributions showed that OC and TN were mainly present in the fine particle fractions (Dp < 1 um). The predominant ions for both cloud and aerosol samples were Cl- and Na+, the primary components of sea salt. However, when air masses arrived from Northwest Africa or from islands upwind of Puerto Rico there was a decrease in Na+ and Cl- concentrations and an increase in SO42-, NH3+ and Ca2+ concentrations, likely reflecting anthropogenic and crustal sources of these species. Overall, the average concentrations of all species are similar to those typically found in background (remote) environments; however, these concentrations showed a significant increase when aged pollution from Northwest Africa and/or fresh pollution from neighboring Caribbean islands reached Puerto Rico. Speciation of nitrogen compounds and details about the size distributions results will also be presented at the conference.
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0320 Cloud physics and chemistry
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting