Browsing by Author "Barata, Filipe"
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- Aerosol chemical elemental mass concentration at lower free tropospherePublication . Freitas, Maria do Carmo; Dionísio, Isabel; Fialho, Paulo; Barata, FilipeThis paper shows the use of Instrumental neutron activation analysis (INAA) technique to determine elemental masses collected by a seven-wavelength Aethalometer instrument at the summit of Pico mountain in the Azorean archipelago, situated in the Central North Atlantic Ocean. Each sample corresponds to air particulate matter measured continuously for periods of approximately 24 h taken from 14th July 2001 through 14th July 2002. The statistical analysis of the coefficients of correlation between all the elements identified, permitted to establish six groups that could potentially be associated with the type of source responsible for the aerosol sampled in the lower free troposphere at the Azorean archipelago. Calculation of the synoptic back trajectories helped to corroborate the use of the iron/cesium relation as a tracer for the Saharan dust aerosol. It was demonstrated that INAA constituted an important tool to identify these events.
- Assessment of air quality on basis of particle matter (PM) measurement in the North Atlantic.Publication . Barata, Filipe; Fialho, Paulo; Pio, CasimiroThe European thematic strategy on air pollution and the accompanying proposal to revise the ambient air quality directive (1999/30/EC) would, for the first time, introduce controls on human expose to PM2.5 to complement the existing limits on coarse particulate matter (PM10) (EC, 2005).
- Black Carbon (BC) and Dust mass concentration measures at North Atlantic Free TropospherePublication . Barata, Filipe; Fialho, PauloThe PICO-NARE observatory is an experimental site on the Pico Island (38.470º; 28.404º; 2225 m altitude) in the Azores Archipelago, developed to provide a base for free troposphere measurements (Richard & Fialho, 2002). One Aethalometer (AE31) was used to determine the aerosol seasonal variability for the Central North Atlantic region. Application of the separation technique, proposed by Fialho et al. (2005,2006), aloud the establishment of the seasonal cycles for BC and Dust.
- Black Carbon (BC) mass concentrations monitoring at North Atlantic Marine Boundary Layer (MBL)Publication . Barata, Filipe; Fialho, PauloThe PICO-NARE observatory is an experimental site on the Pico Island (38.470º; 28.404º; 2225 m altitude) in the Azores Archipelago, developed to provide a base for free troposphere measurements (Richard & Fialho, 2002). One Aethalometer (AE31) was used to determine the aerosol seasonal variability for the Central North Atlantic region. Application of the separation technique, proposed by Fialho et al. (2005,2006), aloud the establishment of the seasonal cycles for BC and Dust.
- Characterisation of carbonaceous aerosols from the Azorean island of TerceiraPublication . Alves, Célia A.; Oliveira, Tiago S.; Pio, Casimiro; Silvestre, Armando J. D.; Fialho, Paulo; Barata, Filipe; Legrand, MichelAerosol samples were collected from 2002 to 2003 in Terceira, one of the islands of the Azores archipelago in the north-eastern Atlantic. The atmospheric samples have been analysed for its carbonaceous content and for lipid class compounds. The major constituents that comprise plant wax are n-alkanes (C23–C33, with and odd-to-even carbon predominance and carbon maxima at 29 or 31), n-alkanols (C22–C30, even-to-odd) and n-alkanoic acids (C22–C30, even-to-odd), with minor amounts of n-alkanals and polycyclic biomarkers, such as phytosterols. Some alkanedioic acids and phthalates were also detected. The occurrence of short-chain homologues may indicate an additional marine source, probably introduced into the atmosphere via sea spray. Changes in the composition of the homologous series derived from terrestrial plants throughout the observation period may be related to alterations in the regional sources and transport pathways. These terrestrial lipids contributed up to 47% of the total compound mass, while the marine input was estimated to be inferior to 19%, both of them being more representative in summer. Biomass burning sources represented approximately 1% of the total inputs to the organic aerosol for the most part of the year, excepting during the spring, when it contributed to 10%. Petroleum products and plasticizers presented higher contributions (up to 19%) during the winter months. Secondary constituents resulting from oxidation during transport varied from 14% to 37% of the apportioned organic mass. The fraction derived from soil resuspension accounted for 2–16%.
- Climatology of aerosol composition (organic versus inorganic) at nonurban sites on a west-east transect across EuropePublication . Pio, Casimiro; Legrand, Michel; Oliveira, Tiago S.; Afonso, Joana; Santos, C.; Caseiro, A.; Fialho, Paulo; Barata, Filipe; Puxbaum, Hans; Sanchez-Ochoa, A.; Kasper-Giebl, Anne; Gelencsér, András; Preunkert, Susanne; Schock, M.In the framework of the European CARBOSOL project (Present and Retrospective State of Organic versus Inorganic Aerosol over Europe: Implications for Climate), atmospheric aerosol was continuously sampled for 2 years at six sites along a west-east transect extending from Azores, in the mid-Atlantic Ocean, to K-Puszta (Hungary), in central Europe. Aerosols were analyzed for ²¹°Pb, inorganic ions, elemental (EC) and organic (OC) carbon, water soluble organic carbon (WSOC), macromolecular type (humic-like) organic substances (HULIS), C2–C5 diacids, cellulose, and levoglucosan. Pooled aerosol filters were also used for the identification of different families of organic compounds by gas chromatography/mass spectrometry, GC/MS, as well as 14C determinations. The data resulted in a climatological overview of the aerosol composition over Europe in the various seasons, from west to east, and from the boundary layer to the free troposphere. The paper first summarizes the characteristics of the sites and collected samples and then focuses on the aerosol mass partitioning (mass closure, inorganic versus organic, EC versus OC, water soluble versus insoluble OC), giving an insight on the sources of carbonaceous aerosol present in rural and natural background areas in Europe. It also introduces the main role of other companion papers dealing with CARBOSOL aerosol data that are also presented in this issue.
- Comparison of Elemental Carbon (EC) and Black Carbon (BC) measurements derived by Thermo-Optical and filter-based light transmission techniques at North Atlantic.Publication . Barata, Filipe; Fialho, Paulo; Pio, CasimiroTerceira Island (38.691º; 27.354º; 50 m altitude) in the Azores Archipelago, developed to provide a base for remote marine boundary layer measurements at a location near the PICO-NARE (Honrath & Fialho, 2002) (Figure 1). In order to determine a long term carbonaceous component of atmospheric aerosols in North Atlantic, measurements of aerosol BC and EC were begun in 2002. EC and BC define similar fraction of the carbonaceous component of atmospheric aerosols and are supposed to be comparable, but have a delicate different thermal, optical and chemical behaviour in most cases (Lavanchy et al., 1999).
- Complexo CLIMAAT-TERCEIRA-NARE para a monitorização da composição da atmosfera na camada limite do Atlântico NortePublication . Fialho, Paulo; Henriques, Diamantino; Carvalho, Fernanda; Barata, Filipe; Azevedo, Eduardo B.As a result of the partnership between the University of Azores, and the Association for the Study of the Insular Environment through the Environment Observatory and the Meteorological Institute, during the 2004 summer it took place the beginning of the installation of the CLIMAAT – TERCEIRA – NARE (INTERREG IIIB – Projecto CLIMAAT – MAC 2.3/A3) platform. In this stage, it was also installed in the José Agostinho observatory, near the city of Angra do Heroísmo, several equipments to monitoring the atmospheric and sun irradiation. Near the coast, at the moment, and beside the meteorological common parameters, pressure, temperature, relative humidity, precipitation, wind direction and intensity some measurements of the black carbon and iron oxide aerosol absorption coefficients were also done. The results of this project should contribute to the study of the evolution and composition of the North Atlantic atmosphere, and in that matter to the study of the Global Changes, namely as a land platform of reference to remote sensing satellite systems. This platform is part of the Azores Global Atmosphere Monitoring Complex (AGAMC).
- Identification of black carbon and dust aerosol events at the Azores PICO-NARE station during the ICARTT experiment.Publication . Fialho, Paulo; Barata, Filipe; Honrath, Richard; Hansen, AnthonyDuring the International Consortium for Atmospheric Research on Transport and Transformation (ICARTT) experiment (July – August 2004), aerosol samples were taken and their aerosol absorption coefficients measured. At the same time the levels of carbon monoxide and ozone where also monitored. These measurements were taken at PICO-NARE site on Pico mountain summit (2225 m ASL) in the Azores Islands. This site is in the pathway of air masses that travel from the surrounding continents (Africa, Europe and North America) that carry with them, among other species, aerosols resulting from combustions (black carbon) and/or natural emissions (dust). In particular, transport from Africa may bring soil dust particles, rich in iron oxides, which are involved in the biogeochemical cycling of iron, an essential micronutrient to marine phytoplankton (Arimoto, Balsam, & Schloesslin, 2002). During this period the sampled masses mainly came form the North American and during sometimes carried with them pollutants resulting from forest fires that occurred in Canada and Alaska.
- Monitorização do Carbono Negro (CN) e Poeiras Minerais (Pm) na Atmosfera do Atlântico NortePublication . Barata, Filipe; Fialho, PauloAs médias anuais da concentração em massa de Carbono Negro (CN) no Atlântico Norte foram de 39 ± 11 ng mˉ³ e de 27 ± ng mˉ³ para a Camada Limite Marinha (CLM) e Troposfera Livre (TL), respectivamente. A variabilidade da concentração em massa de CN, com máximos no período de Verão e mínimos no período de Inverno, indicam que a deposição húmida é o principal mecanismo responsável pelo comportamento sazonal deste poluente da atmosfera. A concentração em massa de Poeiras Minerais (Pm) no Atlântico Norte está associada a episódios curtos, que decorrem essencialmente no mês de Abril, demonstrando a influência de eventos de transporte de longa distância (continente Africano) do aerossol mineral rico em óxidos de ferro (magnetite e hematite), com origem nas emissões de poeiras Saharianas.