MIMiX: a Multipurpose In situ Microreactor system for X-ray microspectroscopy to mimic atmospheric aerosol processing

Forster, JD; Gurk, C; Lamneck, M; Tong, HJ; Ditas, F; Steimer, SS; Alpert, PA; Ammann, M; Raabe, J; Weigand, M; Watts, B; Poschl, U; Andreae, MO; Pohlker, C
2020 | Atmos. Meas. Tech. | 13 (7) (3717-3729)
beamline , cluster-analysis , humidified tdma , hygroscopic growth measurements , ice nucleation , particle critical supersaturation , phase state , physical state , spectromicroscopy , water activities

The dynamic processing of aerosols in the atmosphere is difficult to mimic under laboratory conditions, particularly on a single-particle level with high spatial and chemical resolution. Our new microreactor system for X-ray microscopy facilitates observations under in situ conditions and extends the accessible parameter ranges of existing setups to very high humidities and low temperatures. With the parameter margins for pressure (180-1000 hPa), temperature (similar to 250 K to room temperature), and relative humidity (similar to 0% to above 98 %), a wide range of tropospheric conditions is covered. Unique features are the mobile design and compact size that make the instrument applicable to different synchrotron facilities. Successful first experiments were conducted at two X-ray microscopes, MAXYMUS, located at beamline UE46 of the synchrotron BESSY II, and PolLux, located at beamline X07DA of the Swiss Light Source in the Paul Scherrer Institute. Here we present the design and analytical scope of the system, along with first results from hydration-dehydration experiments on ammonium sulfate and potassium sulfate particles and the tentative observation of water ice at low temperature and high relative humidity in a secondary organic aerosol particle from isoprene oxidation.

Role of the Air-water Interface in Removing Perfluoroalkyl Acids from Drinking Water by Activated Carbon Treatment

Meng, P.; Jiang, X.; Wang, B.; Huang, J.; Wang, Y.; Gang, Y.; Cousins, I.T.; Shubo, D.
2020 | J. Hazard. Mater. | 386 (121981)

Transthyretin-Binding Activity of Complex Mixtures Representing the Composition of Thyroid-Hormone Disrupting Contaminants in House Dust and Human Serum

Hamers, T; Kortenkamp, A; Scholze, M; Molenaar, D; Cenijn, PH; Weiss, JM
2020 | Environ. Health Perspect. | 128 (1)

Dimethylmercury Degradation by Dissolved Sulfide and Mackinawite

West, J; Graham, AM; Van, LN; Jonsson, S
2020 | Environ. Sci. Technol. | 54 (21) (13731-13738)
Potential degradation pathways of dimethylmercury (DMHg) remain as one of the critical knowledge gaps in the marine biogeochemical cycle of mercury (Hg). Although Hg is known to be highly reactive with reduced sulfur, demethylation of DMHg in the presence of sulfide has until now remained experimentally untested. Here, we provide the first experimental support for demethylation of DMHg to monomethylmercury (MMHg) in the presence of both dissolved sulfide and mackinawite (FeS(s)(m)). The degradation of DMHg was shown to be pH dependent, with higher demethylation rates at pH 9 than pH 5. At room temperature and environmentally relevant DMHg to sulfide molar ratios, we observed demethylation rates up to 0.05 d(-1). When comparing the number of active sites available, FeS(s)(m) was found to have a higher capacity to demethylate DMHg, in comparison with dissolved sulfide. Our study suggests that dissolved sulfide and FeS(s)(m) mediated demethylation of DMHg may act as a sink for DMHg, and a potential source of MMHg, in aquatic systems.

Deconvolution of FIGAERO-CIMS thermal desorption profiles using positive matrix factorisation to identify chemical and physical processes during particle evaporation

Buchholz, A; Ylisirnio, A; Huang, W; Mohr, C; Canagaratna, M; Worsnop, D; Schobesberger, S; Virtanen, A
2020 | Atmos. Chem. Phys. | 20 (13) (7693-7716)
absorption-model , alpha-pinene ozonolysis , components , gas , insights , mass-spectrometer , oxidation , secondary organic aerosol , semivolatile , volatility
The measurements of aerosol particles with a filter inlet for gases and aerosols (FIGAERO) together with a chemical ionisation mass spectrometer (CIMS) yield the overall chemical composition of the particle phase. In addition, the thermal desorption profiles obtained for each detected ion composition contain information about the volatility of the detected compounds, which is an important property for understanding many physical properties like gas-particle partitioning. We coupled this thermal desorption method with isothermal evaporation prior to the sample collection to investigate the chemical composition changes during isothermal particle evaporation and particulate-water-driven chemical reactions in alpha-pinene secondary organic aerosol (SOA) of three different oxidative states. The thermal desorption profiles of all detected elemental compositions were then analysed with positive matrix factorisation (PMF) to identify the drivers of the chemical composition changes observed during isothermal evaporation. The keys to this analysis were to use the error matrix as a tool to weight the parts of the data carrying most information (i.e. the peak area of each thermogram) and to run PMF on a combined data set of multiple thermograms from different experiments to enable a direct comparison of the individual factors between separate measurements. The PMF was able to identify instrument background factors and separate them from the part of the data containing particle desorption information. Additionally, PMF allowed us to separate the direct desorption of compounds detected at a specific elemental composition from other signals with the same composition that stem from the thermal decomposition of thermally instable compounds with lower volatility. For each SOA type, 7-9 factors were needed to explain the observed thermogram behaviour. The contribution of the factors depended on the prior isothermal evaporation. Decreased contributions from the factors with the lowest desorption temperatures were observed with increasing isothermal evaporation time. Thus, the factors identified by PMF could be interpreted as volatility classes. The composition changes in the particles due to isothermal evaporation could be attributed to the removal of volatile factors with very little change in the desorption profiles of the individual factors (i.e. in the respective temperatures of peak desorption, T-max). When aqueous-phase reactions took place, PMF was able to identify a new factor that directly identified the ions affected by the chemical processes. We conducted a PMF analysis of the FIGAERO-CIMS thermal desorption data for the first time using laboratory-generated SOA particles. But this method can be applied to, for example, ambient FIGAERO-CIMS measurements as well. There, the PMF analysis of the thermal desorption data identifies organic aerosol (OA) sources (such as biomass burning or oxidation of different precursors) and types, e.g. hydrocarbon-like (HOA) or oxygenated organic aerosol (OOA). This information could also be obtained with the traditional approach, namely the PMF analysis of the mass spectra data integrated for each thermogram. But only our method can also obtain the volatility information for each OA source and type. Additionally, we can identify the contribution of thermal decomposition to the overall signal.

Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

Cai, J; Chu, BW; Yao, L; Yan, C; Heikkinen, LM; Zheng, FX; Li, C; Fan, XL; Zhang, SJ; Yang, DY; Wang, YH; Kokkonen, TV; Chan, T; Zhou, Y; Dada, L; Liu, YC; He, H; Paasonen, P; Kujansuu, JT; Petaja, T; Mohr, C; Kangasluoma, J; Bianchi, F; Sun, YL; Croteau, PL; Worsnop, DR; Kerminen, VM; Du, W; Kulmala, M; Daellenbach, KR
2020 | Atmos. Chem. Phys. | 20 (21) (12721-12740)
air-pollution sources , black carbon , chemical speciation monitor , particulate matter , resolved effective density , seasonal-variations , secondary organic aerosol , source apportionment , source identification , submicron aerosols
Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect particle concentrations. In order to improve estimates of the contribution of primary sources to the particle number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints and particle size distributions measured at the same site in urban Beijing from April to July 2018. Both methods resolved factors related to primary emissions, including vehicular emissions and cooking emissions, which together make up 76% and 24% of total particle number and organic aerosol (OA) mass, respectively. Similar source types, including particles related to vehicular emissions (1.6 +/- 1.1 mu gm(-3); 2.4 +/- 1.8 x 10(3) cm(-3) and 5.5 +/- 2.8 x 10(3) cm(-3) for two traffic-related components), cooking emissions (2.6 +/- 1.9 mu gm(-3) and 5.5 +/- 3.3 x 10(3) cm(-3)) and secondary aerosols (51 +/- 41 mu gm(-3) and 4.2 +/- 3.0 x 10(3) cm(-3)), were resolved by both methods. Converted mass concentrations from particle size distributions components were comparable with those from chemical fingerprints. Size distribution source apportionment separated vehicular emissions into a component with a mode diameter of 20 nm ("traffic-ultrafine") and a component with a mode diameter of 100 nm ("traffic-fine"). Consistent with similar day- and nighttime diesel vehicle PM2.5 emissions estimated for the Beijing area, traffic-fine particles, hydrocarbon-like OA (HOA, traffic-related factor resulting from source apportionment using chemical fingerprints) and black carbon (BC) showed similar diurnal patterns, with higher concentrations during the night and morning than during the afternoon when the boundary layer is higher. Traffic-ultrafine particles showed the highest concentrations during the rush-hour period, suggesting a prominent role of local gasoline vehicle emissions. In the absence of new particle formation, our re-sults show that vehicular-related emissions (14% and 30% for ultrafine and fine particles, respectively) and cooking-activity-related emissions (32 %) dominate the particle number concentration, while secondary particulate matter (over 80 %) governs PM2.5 mass during the non-heating season in Beijing.

Liposome-mediated delivery of challenging chemicals to aid environmental assessment of Bioaccumulative (B) and Toxic (T) properties

Castro, M; Lindqvist, D
2020 | Sci Rep | 10 (1)
acids , daphnia-magna , drug-delivery , fish , hydrophobic chemicals , organic chemicals , substances , systems , volatile
Standard aquatic toxicity tests of chemicals are often limited by the chemicals' water solubility. Liposomes have been widely used in the pharmaceutical industry to overcome poor pharmacokinetics and biodistribution. In this work, liposomes were synthesized and used in an ecotoxicological context, as a tool to assure stable dosing of technically challenging chemicals to zooplankton. Three chemicals with distinctly different characteristics were successfully incorporated into the liposomes: Tetrabromobisphenol A (TBBPA, log K-ow 5.9, pK(a1) 7.5, pK(a2) 8.5), chlorinated paraffin CP-52 (log K-ow 8-12) and perfluorooctanoic acid (PFOA, pK(a) 2.8). The size, production yield and stability over time was similar for all blank and chemical-loaded liposomes, except for when the liposomes were loaded with 10 or 100mgg(-1) PFOA. PFOA increased the size and decreased the production yield and stability of the liposomes. Daphnia magna were exposed to blank and chemical-loaded liposomes in 48hour incubation experiments. A dose-dependent increase in body burden in D. magna and increased immobilization (LD50=7.6ng CPs per individual) was observed. This confirms not only the ingestion of the liposomes but also the successful internalization of chemicals. This study shows that liposomes can be a reliable alternative to aid the study of aquatic toxicity of challenging chemicals.

Composition and volatility of secondary organic aerosol (SOA) formed from oxidation of real tree emissions compared to simplified volatile organic compound (VOC) systems

Ylisirnio, A; Buchholz, A; Mohr, C; Li, ZJ; Barreira, L; Lambe, A; Faiola, C; Kari, E; Yli-Juuti, T; Nizkorodov, SA; Worsnop, DR; Virtanen, A; Schobesberger, S
2020 | Atmos. Chem. Phys. | 20 (9) (5629-5644)
atmospheric chemistry , beta-caryophyllene , boreal forest , flow reactors , gas-phase reaction , mass-spectrometer , norway spruce , oh oxidation , rate coefficient , vapor-pressures
Secondary organic aerosol (SOA) is an important constituent of the atmosphere where SOA particles are formed chiefly by the condensation or reactive uptake of oxidation products of volatile organic compounds (VOCs). The mass yield in SOA particle formation, as well as the chemical composition and volatility of the particles, is determined by the identity of the VOC precursor(s) and the oxidation conditions they experience. In this study, we used an oxidation flow reactor to generate biogenic SOA from the oxidation of Scots pine emissions. Mass yields, chemical composition and volatility of the SOA particles were characterized and compared with SOA particles formed from oxidation of alpha-pinene and from a mixture of acyclic-monocyclic sesquiterpenes (farnesenes and bisabolenes), which are significant components of the Scots pine emissions. SOA mass yields for Scots pine emissions dominated by farnesenes were lower than for a-pinene but higher than for the artificial mixture of farne-senes and bisabolenes. The reduction in the SOA yield in the farnesene- and bisabolene-dominated mixtures is due to exocyclic C =C bond scission in these acyclic-monocyclic sesquiterpenes during ozonolysis leading to smaller and generally more volatile products. SOA particles from the oxi- dation of Scots pine emissions had similar or lower volatility than SOA particles formed from either a single precursor or a simple mixture of VOCs. Applying physical stress to the Scots pine plants increased their monoterpene, especially monocyclic beta-phellandrene, emissions, which further decreased SOA particle volatility and increased SOA mass yield. Our results highlight the need to account for the chemical complexity and structure of real-world biogenic VOC emissions and stress-induced changes to plant emissions when modelling SOA production and properties in the atmosphere. These results emphasize that a simple increase or decrease in relative monoterpene and sesquiterpene emissions should not be used as an indicator of SOA particle volatility.

Open questions on atmospheric nanoparticle growth

Yli-Juuti, T; Mohr, C; Riipinen, I
Cloud droplets form in the atmosphere on aerosol particles, many of which result from nucleation of vapors. Here the authors comment on current knowledge and open questions regarding the condensational growth of nucleated particles to sizes where they influence cloud formation.

Formation and mobilization of methylmercury across natural and experimental sulfur deposition gradients

Akerblom, S; Nilsson, MB; Skyllberg, U; Bjorn, E; Jonsson, S; Ranneby, B; Bishop, K
2020 | Environ. Pollut. | 263
accumulation , acid rain , boreal peatland , dissolved organic matter , global change , mercury , methyl mercury , methylation , nitrogen , peatland , sediments , sulfur , water , yellow perch
We investigated the influence of sulfate (SO42-) deposition and concentrations on the net formation and solubility of methylmercury (MeHg) in peat soils. We used data from a natural sulfate deposition gradient running 300 km across southern Sweden to test the hypothesis posed by results from an experimental field study in northern Sweden: that increased loading of SO42- both increases net MeHg formation and redistributes methylmercury (MeHg) from the peat soil to its porewater. Sulfur concentrations in peat soils correlated positively with MeHg concentrations in peat porewater, along the deposition gradient similar to the response to added SO42- in the experimental field study. The combined results from the experimental field study and deposition gradient accentuate the multiple, distinct and interacting roles of SO42- deposition in the formation and redistribution of MeHg in the environment. (c) 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Screening of halogenated phenolic compounds in plasma and serum from marine wildlife

Lindqvist, D
2020 | Int. J. Environ. Sci. Technol. | 17 (4) (2177-2184)
analysis , bde-47 , bioaccumulation , biotransformation , blood , fate , food , hydroxylated polychlorinated-biphenyls , mass spectral library , pbdes , phenols , polybrominated diphenyl ethers , retention index
The growing knowledge of the impact of halogenated phenolic compounds on hormonal and metabolic systems has led to an increased interest in the exposure and potential effects of these compounds in wildlife. In the present study, a screening procedure was developed to detect and quantify halogenated phenolic compounds in serum and plasma from marine wildlife. A mass spectral library containing selective ion monitoring data was created using gas chromatography electron capture negative ionization mass spectrometry. The selective ion monitoring data in the library were accompanied with retention indices to increase the specificity of each entry in the library. The library together with the developed extraction procedure and optimized instrumental settings can be used for the detection of 52 different halogenated phenolic compounds of environmental concern, including 23 hydroxylated polychlorinated biphenyls and 24 hydroxylated polybrominated diphenyl ethers. The instrument limit of detection for the compounds included in the library ranged from 30 to 320 fg/injection, with a median detection limit of 90 fg/injection. The average recovery of 11 different halogenated phenolic compounds, from four species of marine wildlife, was 66 +/- 14%. A full-scan mass spectral library was also created containing an additional seven compounds. Gray seals, long-tailed ducks, and two species of fish from the Baltic Sea were screened for halogenated phenolic compounds using the developed procedure. A total of 33 compounds included in the library were detected and quantified.

Overview: Integrative and Comprehensive Understanding on Polar Environments (iCUPE) – concept and initial results

Petaja, T; Duplissy, EM; Tabakova, K; Schmale, J; Altstadter, B; Ancellet, G; Arshinov, M; Balin, Y; Baltensperger, U; Bange, J; Beamish, A; Belan, B; Berchet, A; Bossi, R; Cairns, WRL; Ebinghaus, R; El Haddad, I; Ferreira-Araujo, B; Franck, A; Huang, L; Hyvarinen, A; Humbert, A; Kalogridis, AC; Konstantinov, P; Lampert, A; MacLeod, M; Magand, O; Mahura, A; Marelle, L; Masloboev, V; Moisseev, D; Moschos, V; Neckel, N; Onishi, T; Osterwalder, S; Ovaska, A; Paasonen, P; Panchenko, M; Pankratov, F; Pernov, JB; Platis, A; Popovicheva, O; Raut, JC; Riandet, A; Sachs, T; Salvatori, R; Salzano, R; Schroder, L; Schon, M; Shevchenko, V; Skov, H; Sonke, JE; Spolaor, A; Stathopoulos, VK; Strahlendorff, M; Thomas, JL; Vitale, V; Vratolis, S; Barbante, C; Chabrillat, S; Dommergue, A; Eleftheriadis, K; Heilimo, J; Law, KS; Massling, A; Noe, SM; Paris, JD; Prevot, ASH; Riipinen, I; Wehner, B; Xie, ZY; Lappalainen, HK
2020 | Atmos. Chem. Phys. | 20 (14) (8551-8592)
The role of polar regions is increasing in terms of megatrends such as globalization, new transport routes, demography, and the use of natural resources with consequent effects on regional and transported pollutant concentrations. We set up the ERA-PLANET Strand 4 project "iCUPE - integrative and Comprehensive Understanding on Polar Environments" to provide novel insights and observational data on global grand challenges with an Arctic focus. We utilize an integrated approach combining in situ observations, satellite remote sensing Earth observations (EOs), and multi-scale modeling to synthesize data from comprehensive long-term measurements, intensive campaigns, and satellites to deliver data products, metrics, and indicators to stakeholders concerning the environmental status, availability, and extraction of natural resources in the polar areas. The iCUPE work consists of thematic state-of-the-art research and the provision of novel data in atmospheric pollution, local sources and transboundary transport, the characterization of arctic surfaces and their changes, an assessment of the concentrations and impacts of heavy metals and persistent organic pollutants and their cycling, the quantification of emissions from natural resource extraction, and the validation and optimization of satellite Earth observation (EO) data streams. In this paper we introduce the iCUPE project and summarize initial results arising out of the integration of comprehensive in situ observations, satellite remote sensing, and multi-scale modeling in the Arctic context.

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Geovetenskapens Hus,
Svante Arrhenius väg 8, Stockholm

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

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Department of Environmental Science
Stockholm University
106 91 Stockholm

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