Long-range transport and re-circulation of pollutants in the western Mediterranean during the project Regional Cycles of Air Pollution in the West-Central Mediterranean Area

Gangoiti, Gotzon; Millán, Millán M.; Salvador, R.; Mantilla, Enrique

doi:10.1016/s1352-2310(01)00440-x

Cited by 169 publications

(207 citation statements)

References 13 publications

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“…The strong winds blowing constantly from the West (from the Atlantic Ocean) under AA episodes assure fresh clean air with low concentrations of pollutants at regional level, while the WAE and REG episodes involve the stagnation (WAE) and recirculation (REG) of air masses around the WMB for a few days with subsequent accumulation of pollutants. Previous studies in the area based on both modelling and experiments showed that this recirculation/accumulation of pollutants can span for more than five days as long as this weather pattern is maintained (Millán et al, 1992;Gangoiti et al, 2001;Pey et al, 2010).…”

Section: Cluster Analysismentioning

confidence: 96%

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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Section: Cluster Analysismentioning

confidence: 96%

Variability of aerosol optical properties in the Western Mediterranean Basin

et al. 2011

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“…1); 3) the influence of the Iberian and Saharan thermal lows causing weak pressure gradients over the Mediterranean; 4) the intense breeze action along the Mediterranean coast favoured by the prevailing low advective conditions; 5) the scarce summer precipitation; and 6) the intense seasonal contrast concerning temperature, humidity and rainfall (Millán et al, 1997;Soriano et al, 2001;Gangoiti et al, 2001;Rodríguez et al, 2002Rodríguez et al, , 2003Jorba et al, 2004;Pérez et al, 2004). Similarly, the EMB meteorology is controlled by the following main factors: 1) during spring and early summer the development of Saharan depressions to the south of the Atlas Mountains take place (Moulin et al, 1998).…”

Section: Atmospheric Dynamics and Sources Of Pm Along The Mediterraneanmentioning

confidence: 99%

Variability in regional background aerosols within the Mediterranean

et al. 2009

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Abstract. The main objective of this study is the identification of major factors controlling levels and chemical composition of aerosols in the regional background (RB) along the Mediterranean Basin (MB). To this end, data on PM levels and speciation from Montseny (MSY, NE Spain), Finokalia (FKL, Southern Greece) and Erdemli (ERL, Southern Turkey) for the period 2001 to 2008 are evaluated. Important differences on PM levels and composition are evident when comparing the Western and Eastern MBs. The results manifest W-E and N-S PM 10 and PM 2.5 gradients along the MB, attributed to the higher frequency and intensity of African dust outbreaks in the EMB, while for PM 1 very similar levels are encountered.PM in the EMB is characterized by higher levels of crustal material and sulphate as compared to WMB (and central European sites), however, RB nitrate and OC + EC levels are relatively constant across the Mediterranean and lower than other European sites. Marked seasonal trends are evidenced for PM levels, nitrate (WMB), ammonium and sulphate. Also relatively higher levels of V and Ni (WMB) are measured in the Mediterranean basin, probably as a consequence of high emissions from fuel-oil combustion (power generation, industrial and shipping emissions).Enhanced sulphate levels in EMB compared to WMB were measured. The high levels of sulphate in the EMB may deplete the available gas-phase NH 3 so that little ammonium nitrate can form due to the low NH 3 levels.Correspondence to: X. Querol (xavier.querol@idaea.csic.es) This study illustrates the existence of three very important features within the Mediterranean that need to be accounted for when modeling climate effects of aerosols in the area, namely: a) the increasing gradient of dust from WMB to EMB; b) the change of hygroscopic behavior of mineral aerosols (dust) via nitration and sulfation; and c) the abundance of highly hygroscopic aerosols during high insolation (low cloud formation) periods.

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“…The geography and regional meteorological processes in the western Mediterranean also favour the accumulation and ageing of polluted air masses (Gangoiti et al, 2001;Lelieveld et al, 2002;Millán et al, 2000Millán et al, , 2002Millán and Salvador, 1997;Rodríguez et al, 2002;Salvador et al, 1999;Soriano et al, 2001). Arid conditions, combined with high solar radiation and photochemical conversion rates significantly enhance air pollution mostly in the form of PM 2.5 and O 3 .…”

Section: Introductionmentioning

confidence: 99%

Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

et al. 2017

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Abstract. An aerosol time-of-flight mass spectrometer (ATOFMS) was employed to provide real-time single particle mixing state and thereby source information for aerosols impacting the western Mediterranean basin during the ChArMEx-ADRIMED and SAF-MED campaigns in summer 2013. The ATOFMS measurements were made at a ground-based remote site on the northern tip of Corsica.Twenty-seven distinct ATOFMS particle classes were identified and subsequently grouped into eight general categories: EC-rich (elemental carbon), K-rich, Na-rich, amines, OC-rich (organic carbon), V-rich, Fe-rich and Carich particles. Mass concentrations were reconstructed for the ATOFMS particle classes and found to be in good agreement with other co-located quantitative measurements (PM 1 , black carbon (BC), organic carbon, sulfate mass and ammonium mass). Total ATOFMS reconstructed mass (PM 2.5 ) accounted for 70-90 % of measured PM 10 mass and was comprised of regionally transported fossil fuel (EC-rich) and biomass burning (K-rich) particles. The accumulation of these transported particles was favoured by repeated and extended periods of air mass stagnation over the western Mediterranean during the sampling campaigns. The single particle mass spectra proved to be valuable source markers, allowing the identification of fossil fuel and biomass burning combustion sources, and was therefore highly complementary to quantitative measurements made by Particle into Liquid Sampler ion chromatography (PILS-IC) and an aerosol chemical speciation monitor (ACSM), which have demonstrated that PM 1 and PM 10 were comprised predominantly of sulfate, ammonium and OC. Good temporal agreement was observed between ATOFMS EC-rich and K-rich particle mass concentrations and combined mass concentrations of BC, sulfate, ammonium and low volatility oxygenated organic aerosol (LV-OOA). This combined information suggests that combustion of fossil fuels and biomass produced primary EC-and OC-containing particles, which then accumulated ammonium, sulfate and alkylamines during regional transport.Three other sources were also identified: local biomass burning, marine and shipping. Local combustion particlesPublished by Copernicus Publications on behalf of the European Geosciences Union. (emitted in Corsica) contributed little to PM 2.5 particle number and mass concentrations but were easily distinguished from regional combustion particles. Marine emissions comprised fresh and aged sea salt: the former was detected mostly during a 5-day event during which it accounted for 50-80 % of sea salt aerosol mass, while the latter was detected throughout the sampling period. Dust was not efficiently detected by the ATOFMS, and support measurements showed that it was mainly in the PM 2.5-10 fraction. Shipping particles, identified using markers for heavy fuel oil combustion, were associated with regional emissions and represented only a small fraction of PM 2.5 particle number and mass concentration at the site.

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Long-range transport and re-circulation of pollutants in the western Mediterranean during the project Regional Cycles of Air Pollution in the West-Central Mediterranean Area

Cited by 169 publications

References 13 publications

Variability of aerosol optical properties in the Western Mediterranean Basin

Variability of aerosol optical properties in the Western Mediterranean Basin

Variability in regional background aerosols within the Mediterranean

Sources and mixing state of summertime background aerosol in the north-western Mediterranean basin

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