Publications (123) View all
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Dataset: Organic aerosol and global climate modelling: a review
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Article: Chemical Characterization and Source Apportionment of Size-Segregated Aerosol Collected at an Urban Site in Sicily
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ABSTRACT: Aerosol samples were collected at Catania (Italy), from 16 March to 13 June 2005. The sampling was performed using a low pressure five-stage Berner cascade impactor. The samples were analysed for total aerosol mass, Water Soluble Organic Carbon (WSOC), Total Carbon (TC) and main inorganic ionic species. The Water-Insoluble Carbon (WINC) was derived by the difference: TC-WSOC. The samples share some common features: ammonium sulphate and carbon-containing species (both soluble and insoluble) are the largest contributors of fine particle mass, while coarse particles essentially consist of sea-salt, sodium nitrate and unaccounted PM (probably crustal material). The WINC/WSOC ratio decreases from the smallest size range to the large accumulation mode range (0.42–1.2μm), while the \textnssSO = 4 {\text{nssSO}}^{ = }_{4} and \textNH + 4 {\text{NH}}^{ + }_{4} contribution rises. The water-insoluble carbonaceous matter is the dominant component in the smallest particles (0.05–0.14μm). We identified four different aerosol types, corresponding to different sources, contributing to the total particles load of the investigated urban environment: vehicular traffic, producing primary carbonaceous insoluble particles, secondary aerosols, dominating the composition of accumulation mode particles, and marine particles and mineral dust (both important components of the coarse aerosol fraction).Water Air and Soil Pollution 04/2012; 185(1):311-321. · 1.63 Impact Factor -
Article: Chemical Composition of Cloud Water in the Puerto Rican Tropical Trade Wind Cumuli
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ABSTRACT: As part of the Rain In Cumulus over the Ocean Experiment (RICO) and the Puerto Rico Aerosol and Cloud Study (PRACS), cloud water was collected at East Peak (EP) in Puerto Rico. The main objective of this study was to determine the concentrations of water-soluble species (Cl−, NO3 −, SO4 2−, NH4 +, Ca2+, H+, Mg2+, K+, and Na+) in water samples taken from clouds influenced by tropical trade winds. The most abundant inorganic species were Na+ (average 465µeq l−1) and Cl− (434µeq l−1), followed by Mg2+ (105µeq l−1), SO4 2− (61µeq l−1), and NO3 − (25µeq l−1). High concentrations of nss–SO4 2 (28µeq l−1), NO3 − (86µeq l−1), and H+ (14.5µeq l−1) were measured with a shift in air masses origin from the North Atlantic to North American continent, which reflected a strong anthropogenic influence on cloud chemistry at EP. Long-range transport of particles and acid gases seems to be the factor responsible for fluctuations in concentrations and pH of cloud water at East Peak. When under trade wind influences the liquid phase concentrations of all inorganic substances were similar to those found in clouds in other clean maritime environments.Water Air and Soil Pollution 04/2012; · 1.63 Impact Factor -
Article: Atmospheric Chemistry and Physics Determination of the biogenic secondary organic aerosol fraction in the boreal forest by NMR spectroscopy
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ABSTRACT: The study investigates the sources of fine organic aerosol (OA) in the boreal forest, based on measurements in-cluding both filter sampling (PM 1) and online methods and carried out during a one-month campaign held in Hyytiälä, Finland, in spring 2007. Two aerosol mass spectrometers (Q-AMS, ToF-AMS) were employed to measure on-line con-centrations of major non-refractory aerosol species, while the water extracts of the filter samples were analyzed by nuclear magnetic resonance (NMR) spectroscopy for organic func-tional group characterization of the polar organic fraction of the aerosol. AMS and NMR spectra were processed sepa-rately by non-negative factorization algorithms, in order to apportion the main components underlying the submicrome-ter organic aerosol composition and depict them in terms of both mass fragmentation patterns and functional group com-positions. The NMR results supported the AMS speciation of oxi-dized organic aerosol (OOA) into two main fractions, which could be generally labelled as more and less oxidized organ-ics. The more oxidized component was characterized by a mass spectrum dominated by the m/z 44 peak, and in parallel by a NMR spectrum showing aromatic and aliphatic back-bones highly substituted with oxygenated functional groups (carbonyls/carboxyls and hydroxyls). Such component, con-tributing on average 50 % of the OA mass throughout the observing period, was associated with pollution outbreaks from the Central Europe. The less oxidized component was enhanced in concomitance with air masses originating from the North-to-West sector, in agreement with previous investi-gations conducted at this site. NMR factor analysis was able to separate two distinct components under the less oxidized fraction of OA. One of these NMR-factors was associated with the formation of terrestrial biogenic secondary organic aerosol (BSOA), based on the comparison with spectral pro-files obtained from laboratory experiments of terpenes photo-oxidation. The second NMR factor associated with western air masses was linked to biogenic marine sources, and was enriched in low-molecular weight aliphatic amines. Such findings provide evidence of at least two independent sources originating biogenic organic aerosols in Hyytiälä by oxida-tion and condensation mechanisms: reactive terpenes emit-ted by the boreal forest and compounds of marine origin, with the latter relatively more important when predominantly polar air masses reach the site. This study is an example of how spectroscopic techniques, such as proton NMR, can add functional group specificity for certain chemical features (like aromatics) of OA with respect to AMS. They can therefore be profitably exploited to com-plement aerosol mass spectrometric measurements in organic source apportionment studies.Atmospheric Chemistry and Physics 02/2012; 12:941-959. -
Article: General overview: European Integrated project on Aerosol Cloud Climate and Air Quality interactions (EUCAARI) – integrating aerosol research from nano to global scales
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ABSTRACT: In this paper we describe and summarize the main achievements of the European Aerosol Cloud Climate and Air Quality Interactions project (EUCAARI). EUCAARI started on 1 January 2007 and ended on 31 December 2010 leaving a rich legacy including: (a) a comprehensive database with a year of observations of the physical, chemical and optical properties of aerosol particles over Europe, (b) comprehensive aerosol measurements in four developing countries, (c) a database of airborne measurements of aerosols and clouds over Europe during May 2008, (d) comprehensive modeling tools to study aerosol processes fron nano to global scale and their effects on climate and air quality. In addition a new Pan-European aerosol emissions inventory was developed and evaluated, a new cluster spectrometer was built and tested in the field and several new aerosol parameterizations and computations modules for chemical transport and global climate models were developed and evaluated. These achievements and related studies have substantially improved our understanding and reduced the uncertainties of aerosol radiative forcing and air quality-climate interactions. The EUCAARI results can be utilized in European and global environmental policy to assess the aerosol impacts and the corresponding abatement strategies.Atmospheric Chemistry and Physics 01/2012; 11:13061-13143. · 4.88 Impact Factor
