Size-specific distribution of perfluoroalkyl substances (PFASs) in aerosols close to one of the major fluoropolymer manufacturing facilities in China

2019 | SU

SETAC Europe 29th Annual Meeting | May 30, 2019 | Helsinki, Finland

Identification of chemical compounds enriched in the Baltic sea surface microlayer using targeted and non-targeted liquid chromatography mass spectrometry

Johansson, J.; Salter, M.; Wurl, O.; Stolle, C.; Robinson, T-B.; Cousins, I.T.
2019 | SU

SETAC Europe 29th Annual Meeting | May 30, 2019 | Helsinki, Finland

Global transport of perfluoralkyl acids via sea spray aerosol

2019 | Environ. Sci.-Process Impacts | 21 (4) (635-649)

Perfluoroalkyl acids (PFAAs) are persistent organic pollutants found throughout the world's oceans. Previous
research suggests that long-range atmospheric transport of these substances may be substantial. However,
it remains unclear what the main sources of PFAAs to the atmosphere are. We have used a laboratory sea
spray chamber to study water-to-air transfer of 11 PFAAs via sea spray aerosol (SSA). We observed significant
enrichment of all PFAAs relative to sodium in the SSA generated. The highest enrichment was observed in
aerosols with aerodynamic diameter < 1.6 mm, which had aerosol PFAA concentrations up to 62 000 times
higher than the PFAA water concentrations in the chamber. In surface microlayer samples collected from
the sea spray chamber, the enrichment of the substances investigated was orders of magnitude smaller
than the enrichment observed in the aerosols. In experiments with mixtures of structural isomers,
a lower contribution of branched PFAA isomers was observed in the surface microlayer compared to the
bulk water. However, no clear trend was observed in the comparison of structural isomers in SSA and
bulk water. Using the measured enrichment factors of perfluorooctanoic acid and perfluorooctane
sulfonic acid versus sodium we have estimated global annual emissions of these substances to the
atmosphere via SSA as well as their global annual deposition to land areas. Our experiments suggest that
SSA may currently be an important source of these substances to the atmosphere and, over certain
areas, to terrestrial environments.

Spatial variation in the atmospheric deposition of perfluoroalkyl acids: source elucidation through analysis of isomer patterns

2018 | Environ. Sci.: Processes Impacts | 20 (997-1006)

Chemical composition and source analysis of carbonaceous aerosol particles at a mountaintop site in central Sweden

Vera Franke; Paul Zieger; Ulla Wideqvist; Juan Camilo Acosta Navarro; Caroline Leck; Peter Tunved; Bernadette Rosati; Martin Gysel; Matthew Salter; Johan Ström
2017 | Tellus Ser. B-Chem. Phys. Meteorol. | 69 (1)

Revising the hygroscopicity of inorganic sea salt particles

Zieger, P.; Väisänen, O.; Corbin, J.; Partridge, D. G.; Bastelberger, S.; Mousavi-Fard, M.; Rosati, B.; Gysel, M.; Krieger, U.; Leck, C.; Nenes, A.; Riipinen, I.; Virtanen, A.; Salter, M.
2017 | Nat. Commun. | 8 (15883)

Sea spray is one of the largest natural aerosol sources and plays an important role in the Earth’s radiative budget. These particles are inherently hygroscopic, that is, they take-up moisture from the air, which affects the extent to which they interact with solar radiation. We demonstrate that the hygroscopic growth of inorganic sea salt is 8–15% lower than pure sodium chloride, most likely due to the presence of hydrates. We observe an increase in hygroscopic growth with decreasing particle size (for particle diameters <150 nm) that is independent of the particle generation method. We vary the hygroscopic growth of the inorganic sea salt within a general circulation model and show that a reduced hygroscopicity leads to a reduction in aerosol-radiation interactions, manifested by a latitudinal-dependent reduction of the aerosol optical depth by up to 15%, while cloud-related parameters are unaffected. We propose that a value of κs=1.1 (at RH=90%) is used to represent the hygroscopicity of inorganic sea salt particles in numerical models.

Determination of the long-range atmospheric transport potential of perfluoroalkyl acids associated with sea spray aerosols

2016 | Organohalogen Compd. | 78 (233-236)

DIOXIN 2016 | August 28, 2016 | Florence, Italy

Determination of the long-range atmospheric transport potential of perfluoroalkyl acids associated with sea spray aerosols

2016 | Organohalogen Compd. | 78 (233-236)

LOAC: a small aerosol optical counter/sizer for ground-based and balloon measurements of the size distribution and nature of atmospheric particles – Part 2: First results from balloon and unmanned aerial vehicle flights

J.-B. Renard; F. Dulac; G. Berthet; T. Lurton; D. Vignelles; F. Jégou; T. Tonnelier; M. Jeannot; B. Couté; R. Akiki; N. Verdier; M. Mallet; F. Gensdarmes; P. Charpentier; S. Mesmin; V. Duverger; J.-C. Dupont; T. Elias; V. Crenn; J. Sciare; P. Zieger; M. Salter; T. Roberts; J. Giacomoni; M. Gobbi; E. Hamonou; H. Olafsson; P. Dagsson-Waldhauserova; C. Camy-Peyret; C. Mazel; T. Décamps; M. Piringer; J. Surcin; and D. Daugeron
2016 | Atmos. Meas. Tech. | 9 (3673-3686)

In the companion (Part I) paper, we have described and evaluated a new versatile optical particle counter/sizer named LOAC (Light Optical Aerosol Counter), based on scattering measurements at angles of 12 and 60°. That allows for some typology identification of particles (droplets, carbonaceous, salts, and mineral dust) in addition to size-segregated counting in a large diameter range from 0.2 µm up to possibly more than 100 µm depending on sampling conditions (Renard et al., 2016). Its capabilities overpass those of preceding optical particle counters (OPCs) allowing the characterization of all kind of aerosols from submicronic-sized absorbing carbonaceous particles in polluted air to very coarse particles (> 10–20 µm in diameter) in desert dust plumes or fog and clouds. LOAC's light and compact design allows measurements under all kinds of balloons, on-board unmanned aerial vehicles (UAVs) and at ground level. We illustrate here the first LOAC airborne results obtained from a UAV and a variety of scientific balloons. The UAV was deployed in a peri-urban environment near Bordeaux in France. Balloon operations include (i) tethered balloons deployed in urban environments in Vienna (Austria) and Paris (France), (ii) pressurized balloons drifting in the lower troposphere over the western Mediterranean (during the Chemistry-Aerosol Mediterranean Experiment – ChArMEx campaigns), (iii) meteorological sounding balloons launched in the western Mediterranean region (ChArMEx) and from Aire-sur-l'Adour in south-western France (VOLTAIRE-LOAC campaign). More focus is put on measurements performed in the Mediterranean during (ChArMEx) and especially during African dust transport events to illustrate the original capability of balloon-borne LOAC to monitor in situ coarse mineral dust particles. In particular, LOAC has detected unexpected large particles in desert sand plumes.

Calcium enrichment in sea spray aerosol particles

Salter, M.; Hamacher-Barth, E.; Leck, C.; Werner, J.; Johnson, C.; Riipinen, I.; Nilsson, D.; Zieger, P.
2016 | Geophys Res Lett

Sea spray aerosol particles are an integral part of the Earth's radiation budget. To date, the inorganic composition of nascent sea spray aerosol particles have widely been assumed to be equivalent to the inorganic composition of seawater. Here we challenge this assumption using a laboratory sea spray chamber containing both natural and artificial seawater, as well as with ambient aerosol samples collected over the central Arctic Ocean during summer. We observe significant enrichment of calcium in submicrometer (<1μm in diameter) sea spray aerosol particles when particles are generated from both seawater sources in the laboratory as well as in the ambient aerosols samples. We also observe a tendency for increasing calcium enrichment with decreasing particle size. Our results suggest that calcium enrichment in sea spray aerosol particles may be environmentally significant with implications for our understanding of sea spray aerosol, its impact on Earth's climate, as well as the chemistry of the marine atmosphere.

LOAC: a small aerosol optical counter/sizer for ground-based and balloon measurements of the size distribution and nature of atmospheric particles – Part 1: Principle of measurements and instrument evaluation

Renard, J.-B.; Dulac, F.; Berthet, G.; Lurton, T.; Vignelles, D.; Jegou, F.; Tonnelier, T.; Thaury, C., Jeannot, M.; Coute, B.; Akiki, R.; Verdier, N.; Mallet, M.; Gensdarmes, F.; Charpentier, P.; Duverger, V.; Dupont, J.-C.; Mesmin, S.; Elias, T.; Crenn, V.; Sciare, J.; Zieger, P.; Salter, M.; Giacomoni, J.; Gobbi, M.; Hamonou, E.; Olafsson, H.; Dagsson-Waldhauserova, P.; Camy-Peyret, C.; Mazel, C.; Decamps, T.; Piringer, M.; Surcin, J.; Daugeron, D.
2016 | Atmos. Meas. Tech. | 9 (1721-1742)

The study of aerosols in the troposphere and in the stratosphere is of major importance both for climate and air quality studies. Among the numerous instruments available, optical aerosol particles counters (OPCs) provide the size distribution in diameter range from about 100 nm to a few tens of µm. Most of them are very sensitive to the nature of aerosols, and this can result in significant biases in the retrieved size distribution. We describe here a new versatile optical particle/sizer counter named LOAC (Light Optical Aerosol Counter), which is light and compact enough to perform measurements not only at the surface but under all kinds of balloons in the troposphere and in the stratosphere. LOAC is an original OPC performing observations at two scattering angles. The first one is around 12°, and is almost insensitive to the refractive index of the particles; the second one is around 60° and is strongly sensitive to the refractive index of the particles. By combining measurement at the two angles, it is possible to retrieve the size distribution between 0.2 and 100 µm and to estimate the nature of the dominant particles (droplets, carbonaceous, salts and mineral particles) when the aerosol is relatively homogeneous. This typology is based on calibration charts obtained in the laboratory. The uncertainty for total concentrations measurements is ±20 % when concentrations are higher than 1 particle cm−3 (for a 10 min integration time). For lower concentrations, the uncertainty is up to about ±60 % for concentrations smaller than 10−2 particle cm−3. Also, the uncertainties in size calibration are ±0.025 µm for particles smaller than 0.6 µm, 5 % for particles in the 0.7–2 µm range, and 10 % for particles greater than 2 µm. The measurement accuracy of submicronic particles could be reduced in a strongly turbid case when concentration of particles > 3 µm exceeds a few particles  cm−3. Several campaigns of cross-comparison of LOAC with other particle counting instruments and remote sensing photometers have been conducted to validate both the size distribution derived by LOAC and the retrieved particle number density. The typology of the aerosols has been validated in well-defined conditions including urban pollution, desert dust episodes, sea spray, fog, and cloud. Comparison with reference aerosol mass monitoring instruments also shows that the LOAC measurements can be successfully converted to mass concentrations.

An empirically derived inorganic sea spray source function incorporating sea surface temperature

Salter, M. E.; Zieger, P.; Acosta Navarro, J. C.; Grythe, H.; Kirkevag, A.; Rosati, B.; Riipinen, I.; Nilsson, E. D.
2015 | Atmos. Chem. Phys. | 15 (11047-11066)

We have developed an inorganic sea spray source function that is based upon state-of-the-art measurements of sea spray aerosol production using a temperature-controlled plunging jet sea spray aerosol chamber. The size-resolved particle production was measured between 0.01 and 10 μm dry diameter. Particle production decreased non-linearly with increasing seawater temperature (between −1 and 30 °C) similar to previous findings. In addition, we observed that the particle effective radius, as well as the particle surface, particle volume and particle mass, increased with increasing seawater temperature due to increased production of particles with dry diameters greater than 1 μm. By combining these measurements with the volume of air entrained by the plunging jet we have determined the size-resolved particle flux as a function of air entrainment. Through the use of existing parameterisations of air entrainment as a function of wind speed, we were subsequently able to scale our laboratory measurements of particle production to wind speed. By scaling in this way we avoid some of the difficulties associated with defining the "white area" of the laboratory whitecap – a contentious issue when relating laboratory measurements of particle production to oceanic whitecaps using the more frequently applied whitecap method.

The here-derived inorganic sea spray source function was implemented in a Lagrangian particle dispersion model (FLEXPART – FLEXible PARTicle dispersion model). An estimated annual global flux of inorganic sea spray aerosol of 5.9 ± 0.2 Pg yr−1 was derived that is close to the median of estimates from the same model using a wide range of existing sea spray source functions. When using the source function derived here, the model also showed good skill in predicting measurements of Na+ concentration at a number of field sites further underlining the validity of our source function.

In a final step, the sensitivity of a large-scale model (NorESM – the Norwegian Earth System Model) to our new source function was tested. Compared to the previously implemented parameterisation, a clear decrease of sea spray aerosol number flux and increase in aerosol residence time was observed, especially over the Southern Ocean. At the same time an increase in aerosol optical depth due to an increase in the number of particles with optically relevant sizes was found. That there were noticeable regional differences may have important implications for aerosol optical properties and number concentrations, subsequently also affecting the indirect radiative forcing by non-sea spray anthropogenic aerosols.

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Contact information

Visiting addresses:

Geovetenskapens Hus,
Svante Arrhenius väg 8, Stockholm

Arrheniuslaboratoriet, Svante Arrhenius väg 16, Stockholm (Unit for Analytical and Toxicological Chemistry)

Mailing address:
Department of Environmental Science and Analytical Chemistry (ACES)
Stockholm University
106 91 Stockholm

Press enquiries should be directed to:

Stella Papadopoulou
Science Communicator
Phone +46 (0)8 674 70 11