150 research outputs found
Variation of the mixing state of Saharan dust particles with atmospheric transport
No full textMineral dust is an important aerosol species in the Earth’s atmosphere and has a major source within North Africa, of which the Sahara forms the major part. Aerosol Time of Flight Mass Spectrometry (ATOFMS) is first used to determine the mixing state of dust particles collected from the land surface in the Saharan region, showing low abundance of species such as nitrate and sulphate internally mixed with the dust mineral matrix. These data are then compared with the ATOFMS single particle mass spectra of Saharan dust particles detected in the marine atmosphere in the vicinity of the Cape Verde islands, which are further compared with those from particles with longer atmospheric residence sampled at a coastal station at Mace Head, Ireland. Saharan dust particles collected near the Cape Verde Islands showed increased internally mixed nitrate but no sulphate, whilst Saharan dust particles collected on the coast of Ireland showed a very high degree of internally mixed secondary species including nitrate, sulphate and methanesulphonate. This uptake of secondary species will change the pH and hygroscopic properties of the aerosol dust and thus can influence the budgets of other reactive gases, as well as influencing the radiative properties of the particles and the availability of metals for dissolution
Hygroscopicity of marine aerosol: Closure, long term observation and cloud condensation potential
No full textMarine aerosols have a profound impact on the global climate system by scattering solar radiation and serving as seeds for cloud formation. However, the marine aerosols in current models are still poorly represented and lack constraints. In this work, the physico-chemical properties of marine aerosol were obtained in Mace Head Atmospheric Research Station on the west coast of Galway, Ireland. The worked is centred by the data obtained by humidity tandem differential mobility analyzer (HTDMA) and combined with other aerosol measurements, e.g. aerosol mass spectrometer, scanning mobility particle sizer (SMPS). This work aims to characterise marine aerosols in terms of hygroscopicity and their relevant climate impacts and consists of the following sections: • We demonstrate that the hygroscopicity of marine aerosols can be predicted in high temporal resolution by using bulk PM1 chemical composition. This is the first time that the hygroscopicity of marine aerosol has been predicted by the chemical composition that contains sea salt. • We present a statistical analysis of a five-year dataset of hygroscopicity measurement, which is the longest dataset of its kind to date. From this, a contrasting seasonal difference between marine and continental aerosols has been found. • The number concentrations of cloud condensation nuclei (CCN) are predicted by using hygroscopicity and chemical composition. The impact of common assumptions, including size-dependent hygroscopicity and mixing state are quantified. • The sea spray aerosol is one of the most important species of marine aerosol, and the sea spray number is crucial in determining the CCN numbers. However, the sea spray number cannot be measured by conventional methods. As such, we have developed a method to use size-resolved hygroscopicity data to distinguish the sea spray and other species, and we found that the conventional method underestimated the sea spray number by up to tenfold, thus greatly overlooking their climate effects.2025-09-1
Cloud condensation nuclei and hygroscopic growth measurement at Mace Head from 2009 to 2010
No full textThis dataset reports the results of in situ measurements of cloud condensation nuclei (CCN) number concentration, aerosol chemical composition, aerosol hygroscopic growth factor, particle number size distribution collected from 2009 to 2010 at Mace Head Research Station(53.33° N, 9.90 °W; 21m a.m.s.l; 300m from the waterline). This dataset is discussed in a manuscript titled "The impact of aerosol size-dependent hygroscopicity and mixing state on the cloud condensation nuclei over the Northeast Atlantic" by "Wei Xu, Kirsten. Fossum, Jurgita Ovadnevaite, Chunshui Lin, Ru-Jin Huang, Colin O’Dowd, Darius Ceburnis" which is submitted to Atmospheric Chemistry and Physics
Long term observation of sub-saturation hygroscopicity in North Atlantic
No full textThis dataset reports the results of in situ measurements near 5 years aerosol hygroscopic growth factor from 2009 to 2014 at Mace Head Research Station(53.33° N, 9.90 °W; 21m a.m.s.l; 300m from the waterline). This dataset is discussed in a manuscript titled "Seasonal trends of aerosol hygroscopicity and mixing state of clean marine and polluted continental masse at Mace Head" by "Wei Xu, Jurgita Ovadnevaite, Kirsten. Fossum, Chunshui Lin, Ru-Jin Huang, Colin O’Dowd, Darius Ceburnis" which is submitted to Journal of Geophysics Research: Atmospheres
Detecting high contributions of primary organic matter to marine aerosol: a case study
No full textUsing on-line High-Resolution Aerosol Mass Spectrometry, we report submicron organic marine aerosol plume concentrations peaking at 3.8 mu g m(-3). These concentrations are far greater than previously determined by off-line techniques and can exceed typical terrestrial concentrations of organic aerosol. The organic mass comprised 77% of the total submicron non-refractory mass and such plumes were associated with regions of high biological activity and moderately-high wind speeds over the N.E. Atlantic. High-resolution mass spectra analysis revealed a unique marine organic aerosol fingerprint, when compared to anthropogenic organic aerosol, and in particular, anthropogenic hydrocarbons. 37% hydrocarbon and 63% oxygenated hydrocarbon speciation was observed for the organic mass, indicating that at least 37% of the organic mass is produced via primary sea-spray. The hydrocarbon and oxygenated hydrocarbon species were highly correlated (r > 0.99) suggesting a significant, if not dominant, fraction of the oxygenated component is also likely to be sea-spray in origin. Citation: Ovadnevaite, J., C. O'Dowd, M. Dall'Osto, D. Ceburnis, D. R. Worsnop, and H. Berresheim (2011), Detecting high contributions of primary organic matter to marine aerosol: A case study, Geophys. Res. Lett., 38, L02807, doi: 10.1029/2010GL046083.peer-reviewe
Long term observation of sub-saturation hygroscopicity in North Atlantic
No full textThis dataset reports the results of in situ measurements near 5 years aerosol hygroscopic growth factor from 2009 to 2014 at Mace Head Research Station(53.33° N, 9.90 °W; 21m a.m.s.l; 300m from the waterline). This dataset is discussed in a manuscript titled "Seasonal trends of aerosol hygroscopicity and mixing state of clean marine and polluted continental masse at Mace Head" by "Wei Xu, Jurgita Ovadnevaite, Kirsten. Fossum, Chunshui Lin, Ru-Jin Huang, Colin O’Dowd, Darius Ceburnis" which is submitted to Journal of Geophysics Research: Atmospheres
Detecting high contributions of primary organic matter to marine aerosol: a case study
No full textUsing on-line High-Resolution Aerosol Mass Spectrometry, we report submicron organic marine aerosol plume concentrations peaking at 3.8 mu g m(-3). These concentrations are far greater than previously determined by off-line techniques and can exceed typical terrestrial concentrations of organic aerosol. The organic mass comprised 77% of the total submicron non-refractory mass and such plumes were associated with regions of high biological activity and moderately-high wind speeds over the N.E. Atlantic. High-resolution mass spectra analysis revealed a unique marine organic aerosol fingerprint, when compared to anthropogenic organic aerosol, and in particular, anthropogenic hydrocarbons. 37% hydrocarbon and 63% oxygenated hydrocarbon speciation was observed for the organic mass, indicating that at least 37% of the organic mass is produced via primary sea-spray. The hydrocarbon and oxygenated hydrocarbon species were highly correlated (r > 0.99) suggesting a significant, if not dominant, fraction of the oxygenated component is also likely to be sea-spray in origin. Citation: Ovadnevaite, J., C. O\u27Dowd, M. Dall\u27Osto, D. Ceburnis, D. R. Worsnop, and H. Berresheim (2011), Detecting high contributions of primary organic matter to marine aerosol: A case study, Geophys. Res. Lett., 38, L02807, doi: 10.1029/2010GL046083
Seasonality of Aerosol Sources Calls for Distinct Air Quality Mitigation Strategies
No full textAn Aerosol Chemical Speciation Monitor (ACSM) was deployed to investigate the temporal variability of non-refractory particulate matter (NR-PM1) in the coastal city of Galway, Ireland, from February to July 2016. Source apportionment of the organic aerosol (OA) was performed using the newly developed rolling PMF strategy and was compared with the conventional seasonal PMF. Primary OA (POA) factors apportioned by rolling and seasonal PMF were similar. POA factors of hydrocarbon-like OA (HOA), peat, wood, and coal were associated with domestic heating, and with an increased contribution to the OA mass in winter. Even in summer, sporadic heating events occurred with similar diurnal patterns to that in winter. Two oxygenated OA (OOA) factors were resolved, including more-oxygenated OOA and less-oxygenated OOA (i.e., MO-OOA and LO-OOA, accordingly) which were found to be the dominant OA factors during summer. On average, MO-OOA accounted for 62% of OA and was associated with long-range transport in summer. In summer, compared to rolling PMF, the conventional seasonal PMF over-estimated LO-OOA by nearly 100% while it underestimated MO-OOA by 30%. The results from this study show residential heating and long-range transport alternately dominate the submicron aerosol concentrations in this coastal city, requiring different mitigation strategies in different seasons
Primary marine organic aerosol: a dichotomy of low hygroscopicity and high ccn activity
No full textHigh-time resolution measurements of primary marine organic sea-spray physico-chemical properties reveal an apparent dichotomous behavior in terms of water uptake: specifically sea-spray aerosol enriched in organic matter possesses a low hydroscopic Growth Factor (GF similar to 1.25) while simultaneously having a cloud condensation nucleus/condensation nuclei (CCN/CN) activation efficiency of between 83% at 0.25% supersaturation and 100% at 0.75%. In contrast, the activation efficiency of particles dominated by non-sea-salt (nss)-sulfate ranged between 48-100% over supersaturation range of 0.25%-1%. Simultaneous retrieval of Cloud Droplet Number Concentration (CDNC) during primary organic aerosol plumes reveals CDNC concentrations of 350 cm(-3) for organic mass concentrations 3-4 mu g m(-3). It is demonstrated that the retrieved high CDNCs under clean marine conditions can only be explained by organic sea-spray and corroborates the high CCN activation efficiency associated with primary organics. It is postulated that marine hydrogels are responsible for this dichotomous behavior. Citation: Ovadnevaite, J., D. Ceburnis, G. Martucci, J. Bialek, C. Monahan, M. Rinaldi, M. C. Facchini, H. Berresheim, D. R. Worsnop, and C. O\u27Dowd (2011), Primary marine organic aerosol: A dichotomy of low hygroscopicity and high CCN activity, Geophys. Res. Lett., 38, L21806, doi: 10.1029/2011GL048869
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