Sources of carbonaceous aerosol in the Amazon basin

Gilardoni, Stefania; Vignati, E.; Marmer, Elina; Cavalli, F.; Belis, Claudio A.; Gianelle, V.; Loureiro, A.; Artaxo, Paulo

doi:10.5194/acp-11-2747-2011

Cited by 50 publications

(51 citation statements)

References 81 publications

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“…The third protocol is EUSAAR 2 (Cavalli et al, 2010), which has been recently proposed as a standard for carbon analysis on samples collected at European regional background sites. It is noteworthy that few samples analysed in our work by EUSAAR 2 required the last step in oxidising atmosphere to be prolonged in order to obtain a complete carbon evolution, as previously reported by other authors (Kuhlbusch et al, 2009;Gilardoni et al, 2011).…”

Section: Thermal-optical Transmittance Analysissupporting

confidence: 58%

Technical Note: On the effect of water-soluble compounds removal on EC quantification by TOT analysis in urban aerosol samples

et al. 2011

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Abstract. In this work, three different thermal protocols were tested on untreated and water-washed aerosol samples to study the influence of soluble organic and inorganic compounds on EC measurements. Moreover, analyses on the water soluble extracts were carried out. The aim was to find out the most suitable protocol to analyse samples collected in a heavily polluted area. Indeed, the tests were performed on real samples collected at an urban background station in the Po Valley, which is one of the main pollution hot-spots in Europe.The main differences among the tested protocols were the maximum temperature of the He step (i.e. 870 • C, 650 • C, and 580 • C) and the duration of the plateaus during the heating procedure. Our measurements evidenced the presence of a significant amount of weakly light-absorbing carbonaceous aerosol evolving during the highest temperature step in He (i.e. 870 • C), which makes lower temperature protocols not suitable for EC determination in samples collected in heavily polluted areas like Milan.

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Section: Thermal-optical Transmittance Analysissupporting

confidence: 58%

Technical Note: On the effect of water-soluble compounds removal on EC quantification by TOT analysis in urban aerosol samples

et al. 2011

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“…On the other hand, these data points were associated with fairly low aerosol volume concentrations, PV 10 < 1 µm 3 cm −3 . Aerosol chemical characterization at the study site showed that light absorption of BC particles in relatively clean air masses was enhanced by coating effect; this would increase the contribution of absorption to aerosol extinction, increasing the single scattering albedo (Gilardoni et al, 2011). Another explanation could be that some smallscale combustion sources were located in the vicinity of the station so that particle volume did not have time to grow by formation of secondary scattering material (i.e.…”

Section: Aerosol Number Volume and Optical Propertiesmentioning

confidence: 99%

“…Quartz and paper filters were not pretreated prior to analysis. Fine particles (aerodynamic diameter below 2.5 µm) and coarse particles (aerodynamic diameter between 2.5 and 10 µm) were collected simultaneously every 6 days for a collection period of 24 h starting from 08:00 a.m. LT. To avoid negative sampling artefacts due to volatilization of ammonium nitrate from the quartz substrates, a Whatman 41 paper filter was sampled on the back of each quartz filter and the concentration of ammonium and nitrate were calculated as the sum of quartz and paper concentrations (Gilardoni et al, 2009(Gilardoni et al, , 2011. Denuder units were employed to avoid positive sampling artefacts due to absorption of gas species on the sampling substrate.…”

Section: Aerosol Sampling and Analysis Of Chemical Compositionmentioning

confidence: 99%

South African EUCAARI measurements: seasonal variation of trace gases and aerosol optical properties

et al. 2012

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Abstract. In this paper we introduce new in situ observations of atmospheric aerosols, especially chemical composition, physical and optical properties, on the eastern brink of the heavily polluted Highveld area in South Africa. During the observation period between 11 February 2009 and 31 January 2011, the mean particle number concentration (size range 10-840 nm) was 6310 cm −3 and the estimated volume of sub-10 µm particles 9.3 µm 3 m −3 . The aerosol absorption and scattering coefficients at 637 nm were 8.3 Mm −1 and 49.5 Mm −1 , respectively. The mean single-scattering albedo at 637 nm was 0.84 and theÅngström exponent of scattering was 1.5 over the wavelength range 450-635 nm. The mean O 3 , SO 2 , NO x and H 2 S-concentrations were 37.1, 11.5, 15.1 and 3.2 ppb, respectively. The observed range of concentrations was large and attributed to the seasonal variation of sources and regional meteorological effects, especially the anticyclonic re-circulation and strong winter-time inversions. In a global context, the levels of gases and particulates were typical for continental sites with strong anthropogenic influence, but clearly lower than the most polluted areas of southeastern Asia. Of all pollutants observed at the site, ozone is the most likely to have adverse environmental effects, as the concentrations were high also during the growing season. The measurements presented here will help to close existing gaps in the ground-based global atmosphere observation system, since very little long-term data of this nature is available for southern Africa.

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“…Natural biogenic aerosol comprises up to 80 % of PM 10 aerosol mass, with most of the mass (approx. 70 %) in the coarse mode fraction (Echalar et al, 1998;Gerab et al, 1998;Gilardoni et al, 2011). Biogenic particles consist of particles primarily emitted by the vegetation (e.g.…”

Section: T Pauliquevis Et Al: the Role Of Biogenic Contributionmentioning

confidence: 99%

Aerosol and precipitation chemistry measurements in a remote site in Central Amazonia: the role of biogenic contribution

et al. 2012

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Abstract. In this analysis a 3.5 years data set of aerosol and precipitation chemistry, obtained in a remote site in Central Amazonia (Balbina, (1 • 55 S, 59 • 29 W, 174 m a.s.l.), about 200 km north of Manaus) is discussed. Aerosols were sampled using stacked filter units (SFU), which separate fine (d < 2.5 µm) and coarse mode (2.5 µm < d < 10.0 µm) aerosol particles. Filters were analyzed for particulate mass (PM), Equivalent Black Carbon (BC E ) and elemental composition by Particle Induced X-Ray Emission (PIXE). Rainwater samples were collected using a wet-only sampler and samples were analyzed for pH and ionic composition, which was determined using ionic chromatography (IC). Natural sources dominated the aerosol mass during the wet season, when it was predominantly of natural biogenic origin mostly in the coarse mode, which comprised up to 81 % of PM 10 . Biogenic aerosol from both primary emissions and secondary organic aerosol dominates the fine mode in the wet season, with very low concentrations (average 2.2 µg m −3 ). Soil dust was responsible for a minor fraction of the aerosol mass (less than 17 %). Sudden increases in the concentration of elements as Al, Ti and Fe were also observed, both in fine and coarse mode (mostly during the April-may months), which we attribute to episodes of Saharan dust transport. During the dry periods, a significant contribution to the fine aerosols loading was observed, due to the large-scale transport of smoke from biomass burning in other portions of the Amazon basin. This contribution is associated with the enhancement of the concentration of S, K, Zn and BC E . Chlorine, which is commonly associated to sea salt and also to biomass burning emissions, presented higher concentration not only during the dry season but also for the April-June months, due to the establishment of more favorable meteorological conditions to the transport of Atlantic air masses to Central Amazonia. The chemical composition of rainwater was similar to those ones observed in other remote sites in tropical forests. The volume-weighted mean (VWM) pH was 4.90. The most important contribution to acidity was from weak organic acids. The organic acidity was predominantly associated with the presence of acetic acid instead of formic acid, which is more often observed in pristine tropical areas. Wet deposition rates for major species did not differ significantly between dry and wet season, except for NH + 4 , citrate and acetate, which had smaller deposition rates during dry season. While biomass burning emissions were clearly identified in the aerosol component, it did not present a clear signature in rainwater. The biogenic component and the long-range transport of sea salt were observed both in aerosols and rainwater composition. The results shown here indicate that in Central Amazonia it is still possible to observe quite pristine atmospheric conditions, relatively free of anthropogenic influences.

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Sources of carbonaceous aerosol in the Amazon basin

Cited by 50 publications

References 81 publications

Technical Note: On the effect of water-soluble compounds removal on EC quantification by TOT analysis in urban aerosol samples

Technical Note: On the effect of water-soluble compounds removal on EC quantification by TOT analysis in urban aerosol samples

South African EUCAARI measurements: seasonal variation of trace gases and aerosol optical properties

Aerosol and precipitation chemistry measurements in a remote site in Central Amazonia: the role of biogenic contribution

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