Chemical, physical, and optical characterization of aerosols during PAUR II experiment

Kouvarakis, Giorgos; Doukelis, Y.; Mihalopoulos, N.; Rapsomanikis, S.; Sciare, Jean; Blumthaler, M.

doi:10.1029/2000jd000291

Cited by 65 publications

(47 citation statements)

References 25 publications

(54 reference statements)

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“…Ammonium nitrate at the model boundaries was assumed to be zero. This assumption is probably valid for the west, north and south boundaries where the nitrate concentrations in air are very low or associated with sea salt and dust (Kerminen et al, 2001, Kouvarakis et al, 2002. At the eastern boundary, however, the assumed boundary conditions and, hence, the model results for both nitrate and sulphate are highly uncertain and we therefore decided to present results only west of 30 • E.…”

Section: Removal Processes and Boundary Conditionsmentioning

confidence: 99%

Secondary inorganic aerosol simulations for Europe with special attention to nitrate

Loon²,

et al. 2004

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Abstract.Nitrate is an important component of (secondary inorganic) fine aerosols in Europe. We present a model simulation for the year 1995 in which we account for the formation of secondary inorganic aerosols including ammonium sulphate and ammonium nitrate, a semi volatile component. For this purpose, the chemistry-transport model LOTOS was extended with a thermodynamic equilibrium module and additional relevant processes to account for secondary aerosol formation and deposition. During winter, fall and especially spring high nitrate levels are projected over north western, central and eastern Europe. During winter nitrate concentrations are highest in Italy, in accordance with observed data. In winter nitric acid, the precursor for aerosol nitrate is formed through heterogeneous reactions on the surface of aerosols. Modelled and observed sulphate concentrations show little seasonal variation. Compared to sulphate levels, appreciable ammonium nitrate concentrations in summer are limited to those areas with high ammonia emissions, e.g. the Netherlands, since high ammonia concentrations are necessary to stabilise this aerosol component at high temperatures. As a consequence of the strong seasonal variation in nitrate levels the AOD depth of nitrate over Europe is especially significant compared to that of sulphate in winter and spring when equal AOD values are calculated over large parts of Europe. Averaged over all stations the model reproduces the measured concentrations for NO 3 , SO 4 , NH 4 , TNO 3 (HNO 3 +NO 3 ), TNH 4 (NH 3 +NH 4 ) and SO 2 within 20%. The daily variation is captured well, albeit that the model does not always represent the amplitude of single events. The model underestimates wet deposition which was attributed to the crude representation of cloud processes.Comparison of retrieved and computed aerosol optical depth (AOD) showed that the model underestimates AOD signifiCorrespondence to: M. Schaap (m.schaap@mep.tno.nl) cantly, which was expected due to the lack of carbonaceous aerosols, sea salt and dust in the model. The treatment of ammonia was found to be a major source for uncertainties in the model representation of secondary aerosols. Also, inclusion of sea salt is necessary to properly assess the nitrate and nitric acid levels in marine areas.

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Section: Removal Processes and Boundary Conditionsmentioning

confidence: 99%

Secondary inorganic aerosol simulations for Europe with special attention to nitrate

Loon²,

et al. 2004

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“…As shown in this work, the in-situ measurements are helpful in order to describe the effects of mesoscale weather systems such as the breeze circulation on aerosol optical properties. A number of studies have been published on in-situ aerosol optical measurements in the Eastern Mediterranean (Vrekoussis et al, 2005;Ichoku et al, 1999;Formenti et al, 2001;Sciare et al, 2005;Kouvarakis et al, 2002;Andreae et al, 2002;Gerasopoulos et al, 2003;Sabbah et al, 2001;Israelevich et al, 2002), Central Mediterranean and South Italy (Pace et al, 2006;Esposito et al, 2004), South Iberian Peninsula (Pereira et al, 2011;Lyamani et al, 2008). However, little has been published on aerosol optical properties in the Western Mediterranean Basin (Mallet et al, 2003;Saha et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Variability of aerosol optical properties in the Western Mediterranean Basin

et al. 2011

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Abstract. Aerosol light scattering, absorption and particulate matter (PM) concentrations were measured at Montseny, a regional background site in the Western Mediterranean Basin (WMB) which is part of the European Supersite for Atmospheric Aerosol Research (EUSAAR). Off line analyses of 24 h PM filters collected with Hi-Vol instruments were performed for the determination of the main chemical components of PM. Mean scattering and hemispheric backscattering coefficients (@ 635 nm) were 26.6±23.2 Mm −1 and 4.3±2.7 Mm −1 , respectively and the mean aerosol absorption coefficient (@ 637 nm) was 2.8±2.2 Mm −1 . Mean values of Single Scattering Albedo (SSA) andÅngström exponent (å) (calculated from 450 nm to 635 nm) at MSY were 0.90±0.05 and 1.3±0.5 respectively. A clear relationship was observed between the PM 1 /PM 10 and PM 2.5 /PM 10 ratios as a function of the calculatedÅngström exponents. Mass scattering cross sections (MSC) for fine mass and sulfate at 635 nm were 2.8±0.5 m 2 g −1 and 11.8±2.2 m 2 g −1 , respectively, while the mean aerosol absorption cross section (MAC) was 10.4±2.0 m 2 g −1 . The variability in aerosol optical properties in the WMB were largely explained by the origin and ageing of air masses over the measurement site. The MAC values appear dependent of particles aging: similar to the expected absorption cross-section for fresh emissions under Atlantic Advection episodes and higher under aerosol pollution episodes. The analysis of theÅngström exponent as a function of the origin the air masses revealed that polluted winter anticyclonic conditions and summer recirculation scenarios typical of the WMB led to an increase of fine particles in the atmosphere (å = 1.5±0.1) while the aerosol optical properties under Atlantic Advection episodes and Saharan dust outbreaks were clearly dominated by coarser particles (å = 1.0±0.4). The sea breeze played an important role Correspondence to: M. Pandolfi (marco.pandolfi@idaea.csic.es) in transporting pollutants from the developed WMB coastlines towards inland rural areas, changing the optical properties of aerosols. Aerosol scattering and backscattering coefficients increased by around 40 % in the afternoon when the sea breeze was fully developed while the absorption coefficient increased by more than 100 % as a consequence of the increase in the equivalent black carbon concentration (EBC) observed at MSY under sea breeze circulation.

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“…In addition, Mihalopoulos et al (1997) and Kouvarakis et al (2002) reported for the same area a significant chloride deficit in the aerosol phase relative to sodium, indicating potential presence of Cl atoms in the gas phase. Indeed, this deficit is attributed to the reactions of sodium chloride (NaCl) with acidic species such as sulphuric acid (H 2 SO 4 ) and nitric acid (HNO 3 ) present also at relatively high levels in the Mediterranean atmosphere (Bardouki et al, 2003;Metzger et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Tropospheric OH and Cl levels deduced from non-methane hydrocarbon measurements in a marine site

et al. 2007

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Abstract. In situ continuous hourly measurements of C 2 -C 8 non-methane hydrocarbons (NMHC S ) have been performed from March to October 2006 at two coastal locations (natural and rural) on the island of Crete, in the Eastern Mediterranean. Well defined diel variations were observed for several short lived NMHC S (including ethene, propene, n-butane, n-pentane, n-hexane, 2-methyl-pentane). The daytime concentration of hydroxyl (OH) radicals estimated from these experimental data varied from 1.3×10 6 to ∼4.0×10 6 radical cm −3 , in good agreement with boxmodel simulations. In addition the relative variability of various hydrocarbon pairs (at least 7) was used to derive the tropospheric levels of Cl atoms. The Cl atom concentration has been estimated to range between 0.6×10 4 and 4.7×10 4 atom cm −3 , in good agreement with gaseous hydrochloric acid (HCl) observations in the area. Such levels of Cl atoms can be of considerable importance for the oxidation capacity of the troposphere on a regional scale.

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Chemical, physical, and optical characterization of aerosols during PAUR II experiment

Cited by 65 publications

References 25 publications

Secondary inorganic aerosol simulations for Europe with special attention to nitrate

Secondary inorganic aerosol simulations for Europe with special attention to nitrate

Variability of aerosol optical properties in the Western Mediterranean Basin

Tropospheric OH and Cl levels deduced from non-methane hydrocarbon measurements in a marine site

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