Composition and properties of atmospheric particles in the eastern Atlantic and impacts on gas phase uptake rates

Allan, J. D.; Topping, David; Good, N.; Irwin, M.; Flynn, Michael J.; Williams, P. I.; Coe, Hugh; Baker, Alex R.; Martino, Manuela; Niedermeier, N.; Wiedensohler, Alfred; Lehmann, Stefan; Müller, Konrad; Herrmann, Hartmut; McFiggans, G.

doi:10.5194/acp-9-9299-2009

Cited by 67 publications

(74 citation statements)

References 81 publications

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“…This disagreement is likely due to the different approach used to derive clean marine OM values for ICEALOT (i.e., Positive Matrix Factorization). Our mean OM value (0.77 µg m −3 , see Table 1) is higher than the number obtained by Allan et al (2009) during RHaBMLe for their "clean" 40-h period (0.29 µg m −3 ), identified based on the back trajectories analysis. Their criteria were more conservative and they excluded time periods with measurements exhibiting high variability in composition and air mass history.…”

Section: Measurements Of Aerosol Compositionmentioning

confidence: 67%

Investigating organic aerosol loading in the remote marine environment

et al. 2011

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Abstract. Aerosol loading in the marine environment is investigated using aerosol composition measurements from several research ship campaigns (ICEALOT, MAP, RHaMBLe, VOCALS and OOMPH), observations of total AOD column from satellite (MODIS) and ship-based instruments (Maritime Aerosol Network, MAN), and a global chemical transport model (GEOS-Chem). This work represents the most comprehensive evaluation of oceanic OM emission inventories to date, by employing aerosol composition measurements obtained from campaigns with wide spatial and temporal coverage. The model underestimates AOD over the remote ocean on average by 0.02 (21 %), compared to satellite observations, but provides an unbiased simulation of ground-based Maritime Aerosol Network (MAN) observations. Comparison with cruise data demonstrates that the GEOS-Chem simulation of marine sulfate, with the mean observed values ranging between 0.22 µg m −3 and 1.34 µg m −3 , is generally unbiased, however surface organic matter (OM) concentrations, with the mean observed concentrations between 0.07 µg m −3 and 0.77 µg m −3 , are underestimated by a factor of 2-5 for the standard model run. Addition of a sub-micron marine OM source of approximately 9 TgC yr −1 brings the model into agreement with the ship-based measurements, however this additional OM source does not exCorrespondence to: K. Lapina (klapina@atmos.colostate.edu) plain the model underestimate of marine AOD. The model underestimate of marine AOD is therefore likely the result of a combination of satellite retrieval bias and a missing marine aerosol source (which exhibits a different spatial pattern than existing aerosol in the model).

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Section: Measurements Of Aerosol Compositionmentioning

confidence: 67%

Investigating organic aerosol loading in the remote marine environment

et al. 2011

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“…However, the lack of a high growth factor mode in the HTDMA-CPC (e.g. Allan et al, 2009) would suggest that sea salt is not an important contributor to the number concentrations at the dry sizes under investigation here. As the AMS does not measure sea salt, it is difficult to critically assess whether including this improves closure.…”

Section: Growth Factor Modellingmentioning

confidence: 99%

Ambient black carbon particle hygroscopic properties controlled by mixing state and composition

et al. 2013

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The wet removal of black carbon aerosol (BC) in the atmosphere is a crucial factor in determining its atmospheric lifetime and thereby the vertical and horizontal distributions, dispersion on local and regional scales, and the direct, semi-direct and indirect radiative forcing effects. The in-cloud scavenging and wet deposition rate of freshly emitted hydrophobic BC will be increased on acquisition of more-hydrophilic components by coagulation or coating processes. The lifetime of BC is still subject to considerable uncertainty for most of the model inputs, which is largely due to the insufficient constraints on the BC hydrophobic-to-hydrophilic conversion process from observational field data. This study was conducted at a site along UK North Norfolk coastline, where the BC particles were transported from different regions within Western Europe. A hygroscopicity tandem differential mobility analyser (HTDMA) was coupled with a single particle soot photometer (SP2) to measure the hygroscopic properties of BC particles and associated mixing state in real time. In addition, a Soot Particle AMS (SP-AMS) measured the chemical compositions of additional material associated with BC particles. The ensemble of BC particles persistently contained a less-hygroscopic mode at a growth factor (gf) of around 1.05 at 90% RH (dry diameter 163 nm). Importantly, a more-hygroscopic mode of BC particles was observed throughout the experiment, the gf of these BC particles extended up to ~1.4–1.6 with the minimum between this and the less hygroscopic mode at a gf ~1.25, or equivalent effective hygroscopicity parameter κ ~0.1. The gf of BC particles (gfBC) was highly influenced by the composition of associated soluble material: increases of gfBC were associated with secondary inorganic components, and these increases were more pronounced when ammonium nitrate was in the BC particles; however the presence of secondary organic matter suppressed the gfBC below that of pure inorganics. The Zdanovskii-Stokes-Robinson (ZSR) mixing rule captures the hygroscopicity contributions from different compositions within ±30% compared to the measured results, however is subject to uncertainty due to the complex morphology of BC component and potential artefacts associated with semivolatile particles measured with the HTDMA. This study provides detailed insights on BC hygroscopicity associated with its mixing state, and the results will importantly constrain the microphysical mixing schemes of BC as used by a variety of high level models. In particular, this provides direct evidence to highlight the need to consider ammonium nitrate ageing of BC particles because this will result in particles becoming hydrophilic on much shorter timescales than for sulphate formation, which is often the only mechanism considered

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“…Elemental carbon (EC) during the subtropical events in the Miyazaki et al (2010) study averaged 43 ng m −3 . Less directly, hygroscopic growth experiments in the Southern Atlantic and Indian Oceans (Maßling, 2003), the Pacific and Southern Oceans (Berg et al, 1998), near Puerto Rico (Allan et al, 2008) and the Eastern Atlantic (Allan et al, 2009) all found hygroscopic growth of aerosol particles consistent with particles composed chiefly of sulfate salts rather than OM during clean marine periods.…”

Section: M Shank Et Al: Organic Matter and Non-refractory Aerosolmentioning

confidence: 99%

Organic matter and non-refractory aerosol over the remote Southeast Pacific: oceanic and combustion sources

et al. 2012

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(SO 4 ) and organics (Org), during VOCALS and the cruise show lower absolute values than those reported for previous "clean air" studies. In the marine boundary layer, average concentrations for SO 4 were 0.52 µg m −3 for the VOCALS region and 0.85 µg m −3 for the equatorial region while average Org concentrations were 0.10 and 0.07 µg m −3 , respectively. Campaign average Org/SO 4 ratios were 0.19 (VOCALS) and 0.08 (equatorial Pacific). Black carbon (BC) measurements from a single particle soot photometer (SP2) and carbon monoxide (CO) concentrations over the Southeast Pacific provided sensitive indicators of pollution. CO and BC were used to identify the least polluted air, which had average concentrations of SO 4 and Org of 0.14 and 0.01 µg m −3 , respectively, with an average Org/SO 4 of 0.08. Data from IMPEX was constrained to similar clean air criterion, and resulted in an average Org/SO 4 ratio of 0.19. Under the cleanest MBL conditions during VOCALS, identified by CO below 61 ppbv, a robust linear relationship between Org and BC concentrations revealed that even at very low pollution levels, combustion sources dominated organic aerosol, suggesting little to no marine source of submicrometer Org to the atmosphere over the eastern South Pacific. This means marine organics cannot be identified by merely setting a standard for background conditions below which anthropogenic influence can be disregarded. Other methods must be used to exclude nonmarine sources.

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Composition and properties of atmospheric particles in the eastern Atlantic and impacts on gas phase uptake rates

Cited by 67 publications

References 81 publications

Investigating organic aerosol loading in the remote marine environment

Investigating organic aerosol loading in the remote marine environment

Ambient black carbon particle hygroscopic properties controlled by mixing state and composition

Organic matter and non-refractory aerosol over the remote Southeast Pacific: oceanic and combustion sources

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